A4 revving issue while at low speeds?

[wildcat333]

Hello. New member here, but just wanted to see if anyone has ever had an issue similar to mine. I just picked up this 08 CPO A4 (automatic) with 38,000 miles on it.

While driving in drive at a steady speed of approx 30 mph, the tachometer revs slightly up and down. I keep my foot steady, and am not accelerating or slowing down at all. I can visually see the tach move some (about 300 rpm's) up and down; and I can also hear a slight engine noise while it does this.

Any ideas? Is this normal, or should I get this checked out? Solutions?

Thank you.

[Inked]

search 'rpm fluctuations' theres a number of things.

1. replace n80 vavle - n80

2. jb weld fitting - JB weld-the best thing ever

3. transmission fluid - ATF replace

Your Welcome.

[wildcat333]

Excellent - thank you very much. Just another quick question:

Do you think this would be covered by the Certified Pre-owned Warranty? Would Audi be willing to check out my issue, and then determine if it is covered or not?

(Again, I've only had my Audi for 4 days, so I'm learning). Thanks.

[rune]

Hello. New member here, but just wanted to see if anyone has ever had an issue similar to mine. I just picked up this 08 CPO A4 (automatic) with 38,000 miles on it.

While driving in drive at a steady speed of approx 30 mph, the tachometer revs slightly up and down. I keep my foot steady, and am not accelerating or slowing down at all. I can visually see the tach move some (about 300 rpm's) up and down; and I can also hear a slight engine noise while it does this.

Any ideas? Is this normal, or should I get this checked out? Solutions?

Thank you.

I have the same problem on my 06 A4 2.0tfsi Tip. Changing vacum pump did not work (JB weld) for me.
Slippage is a common TC problem, and causes your car to resist acceleration while engine continues to rev. The most common cause is low or overheated trans fluid. So i will check my fluid level first. then see what happens. Possibly change oil and filter.
I have not tried to change my N80 valve yet, but i will do it after i check my trans fluid if i still have the RPM variation then.
Check with your Audi dealer abouet warranty, i think you have it.
Good luck, let me know how it goes.

[Leo14]

Lol take it back to the dealer man, be like hi I have warranty fix this kthx

[Macdoon]

Hi Wild

About 2 weeks ago my B7 strangely over revved a few times while driving at various speeds, the once it under revved, strange!!! anyways took it back to Audi, they have replaced the Inlet manifold as the there was a leak from the seal (complete unit replaced), this seems to have done the trick, or at least no more symptoms.

Mac

[rune]

Hi Wild

About 2 weeks ago my B7 strangely over revved a few times while driving at various speeds, the once it under revved, strange!!! anyways took it back to Audi, they have replaced the Inlet manifold as the there was a leak from the seal (complete unit replaced), this seems to have done the trick, or at least no more symptoms.

Mac

Do you have tiptronic ?

[Macdoon]

Do you have tiptronic ?

No mate

[rune]

No mate

interesting, did you have any codes or warning from instrumentpanel ?

[wildcat333]

Hi Wild

About 2 weeks ago my B7 strangely over revved a few times while driving at various speeds, the once it under revved, strange!!! anyways took it back to Audi, they have replaced the Inlet manifold as the there was a leak from the seal (complete unit replaced), this seems to have done the trick, or at least no more symptoms.

Mac

Thanks, Mac.

I called my local Audi dealership yesterday to tell them about my slight issue. The shop asked if I was experiencing this RPM fluctuation only while having the defrost on. I said couldn't recall, and I'd call back if needed. I feel that my RPMs move erratically randomly while going 25mph for example. It does not matter if I have the defrost on or not.

QUESTION ABOUT THE AUDI CERTIFIED PREOWNED WARRANTY:

I asked the dealer how this works in general. He said no matter what, I would have to pay approx $80 for the CPO deductible if it was a covered item. He said if they spent the time to look at it, and found nothing unusual, I'd have to pay approx $180 for their time/labor. Is this normal? I didn't read ALL of the CPO fine print yet. My main worry is that I cannot replicate this RPM issue 100% of the time. It does it randomly (both hot and cold engine). I want to get this checked out, but also cannot afford to get hosed for more $$$.

[rune]

Thanks, Mac.

I called my local Audi dealership yesterday to tell them about my slight issue. The shop asked if I was experiencing this RPM fluctuation only while having the defrost on. I said couldn't recall, and I'd call back if needed. I feel that my RPMs move erratically randomly while going 25mph for example. It does not matter if I have the defrost on or not.

QUESTION ABOUT THE AUDI CERTIFIED PREOWNED WARRANTY:



I asked the dealer how this works in general. He said no matter what, I would have to pay approx $80 for the CPO deductible if it was a covered item. He said if they spent the time to look at it, and found nothing unusual, I'd have to pay approx $180 for their time/labor. Is this normal? I didn't read ALL of the CPO fine print yet. My main worry is that I cannot replicate this RPM issue 100% of the time. It does it randomly (both hot and cold engine). I want to get this checked out, but also cannot afford to get hosed for more $$$.

Is it worse when cold ? I have it just in the start up fase until the engine get's warm, then it goes away. But i think we have the same issues. No codes.
Like said up here, check oil level on tranny. I will have mine checked hopefully this week and logg it with vagcom.

[wildcat333]

Is it worse when cold ? I have it just in the start up fase until the engine get's warm, then it goes away. But i think we have the same issues. No codes.
Like said up here, check oil level on tranny. I will have mine checked hopefully this week and logg it with vagcom.

It varies - it can do the same rpm fluxuation while either super cold, or after driving for a while, and plenty hot. I called the dealership today. They said they would take it for a test drive to see if they agree that it has a problem (for free). I really hope when I bring it to them, the issue actually happens again. It's not constant, so we'll see. I even had my friend ride with me, to make sure I wasn't crazy, haha. I'll report back for sure later this week. I think I'm going to bring it in Thursday or Friday.

[wildcat333]

I took a video of the RPM flucuation and threw it on youtube in case anyone is interested in what I was talking about:



UPDATE:

I took it to the dealer today (Friday, 03/04/11). I went for a drive with the lead mechanic. Of course, it drove fine with no RPM issues. I showed the video above that I had on my phone to him, which allowed him to investigate the issue further. After about three hours of working on it, they fixed the problem. I'll write word for word what the dealer wrote on my slip:

"Customer road tested with shop foreman. Confirmed customer complaint - engine RPM surge on steady speed. Checked ECM for faults, no faults stored on ECM, checked engine over, found small vacuum leak coming from breather valve, removed breather valve, applied pressure on the intake side, valve is not holding pressure, causing turbo boost to enter engine breather system, making RMP's go up and down at a steady speed. Replaced breather valve and updated breather hose. Road tested vehicle, set readiness code. Engine is performing to manufacture specs."

The slip says it would have cost $197.61 without warranty. I paid nothing out of pocket. CPO FTW. Car drives perfectly. Very happy.

[groundround]

does it idle like that while stopped or in neutral? Mine did that and audi could not figure out what it was. ended up being the PCV valve

[rune]

I took a video of the RPM flucuation and threw it on youtube in case anyone is interested in what I was talking about:

http://www.youtube.com/watch?v=kdmL68HIBVE

UPDATE:

I took it to the dealer today (Friday, 03/04/11). I went for a drive with the lead mechanic. Of course, it drove fine with no RPM issues. I showed the video above that I had on my phone to him, which allowed him to investigate the issue further. After about three hours of working on it, they fixed the problem. I'll write word for word what the dealer wrote on my slip:

"Customer road tested with shop foreman. Confirmed customer complaint - engine RPM surge on steady speed. Checked ECM for faults, no faults stored on ECM, checked engine over, found small vacuum leak coming from breather valve, removed breather valve, applied pressure on the intake side, valve is not holding pressure, causing turbo boost to enter engine breather system, making RMP's go up and down at a steady speed. Replaced breather valve and updated breather hose. Road tested vehicle, set readiness code. Engine is performing to manufacture specs."

The slip says it would have cost $197.61 without warranty. I paid nothing out of pocket. CPO FTW. Car drives perfectly. Very happy.

Good news and congratulations , i will check mine too When i see your video, mine is performing the same.

This part you changed ? http://www.ecstuning.com/Audi-B7_A4-...reather_Valve/

[Slovak84]

Also have been having this problem, It started this winter.... The car fluctuates usually 100rpm up and down when accelerating before engine fully warms up. Once the engine is around normal Op temp the fluctuating just stops and needle remains steady. A lot of ppl are having this issue lately...

[wildcat333]

groundround - It only did that while driving. Definitely not in parked. I drive auto tiptronic, so I'm rarely in neutral, so I am not sure about that. It would do it between 20-70 mph at various points.

rune - Thanks! It feels like a new car - like it should since it's two weeks old to me haha!!. I really cannot say as far as a part number. I'm not an expert on these things or car parts, so I don't want to mess you up anyhow. My slip that they gave me only said the information I posted above in the red font. It's possible though.. most likely I'd say. Also, how's Norway? I hear it's a fun and cool place to be!

[rune]

groundround - It only did that while driving. Definitely not in parked. I drive auto tiptronic, so I'm rarely in neutral, so I am not sure about that. It would do it between 20-70 mph at various points.

rune - Thanks! It feels like a new car - like it should since it's two weeks old to me haha!!. I really cannot say as far as a part number. I'm not an expert on these things or car parts, so I don't want to mess you up anyhow. My slip that they gave me only said the information I posted above in the red font. It's possible though.. most likely I'd say. Also, how's Norway? I hear it's a fun and cool place to be!

I am fine thank you, just waiting for the winter to go away. It's been very cold for long time and i am glad it's spring time soon.
How is it 'over there' ?
Just hope my car will be fixed soon, i already bought this valve at the audi shop, http://www.ecstuning.com/Audi-B7_A4-...reather_Valve/
Let us hope it's the right one

[wildcat333]

another update:

I am not happy to say this, but the rpm fluctuations are back. Now they only happen when the car is cold, during the first 10+ minutes of driving. The movement in the tach is virtually the same as the above video. To me though, this is not acceptable. I live close to my job, and often will only drive 15 miles in a day. The problem is that I live about one hour from the dealership. By the time I drive it to the dealer, the engine is nice and warm, and does not show any issues when I get there for their test drive. I will call tomorrow, attempt to arrange a drop-off to let them work on it over a day or two. I hope they will give me a loaner car, as I really don't want my car back until it is completely fixed. A two week old CPO A4 should not have these issues. I will report back (obviously) as to what I find out.

Also, when the RPM's rev up and down, the engine or something makes terrible noises. It sounds like a am about to break down!

[wildcat333]

update as of Sunday 03/06/11 @ 3:40 PM EST:

To clarify, I had the dealer repairs done on Friday. I had the RPM issues Saturday morning, when it was cold outside. It is about 52 degrees (F) outside today (Sunday), and I did not have any issues. I'm wondering if it only happens during very cold weather. I am going to hold off on any dealer service until this happens to me again. If it does, I'll be gung-ho for repairs!!

I was glad again to see the car running properly. I even ended up driving on some dirt/muddy country roads in heavy fog conditions. I love the auto Sport gear mode. So fun/fast. APR chip possibly in late spring....?!!

[rune]

update as of Sunday 03/06/11 @ 3:40 PM EST:

To clarify, I had the dealer repairs done on Friday. I had the RPM issues Saturday morning, when it was cold outside. It is about 52 degrees (F) outside today (Sunday), and I did not have any issues. I'm wondering if it only happens during very cold weather. I am going to hold off on any dealer service until this happens to me again. If it does, I'll be gung-ho for repairs!!

I was glad again to see the car running properly. I even ended up driving on some dirt/muddy country roads in heavy fog conditions. I love the auto Sport gear mode. So fun/fast. APR chip possibly in late spring....?!!

Good, i will follow this thread.

I can see some oilgrease and dirt around the PCV, and i have the parts so will go to dealer to change them.
Someone told me to check the oil level in the tranny, cause if it's too low it can cause RPM jumps when cold. Cold oil is thicker than warmed up oil, maybe a lock up valve can be hanging or bad ? i will check this up.
Sportmode is fun to drive with and it's a big difference too D mode.

Do you know if there is taken a service on your tranny, oil/filter ?

[wildcat333]

rune - According to my CPO paperwork (certified last month/ about 700 miles ago), they changed the tranny fluid, and also changed the oil/filter.

I called the dealer today, because it is acting up again as of today (Monday). It is less severe than the video I posted, but the car still makes awful noises when the rpm's move. I have figured out at least one way to replicate the issue most of the time >>> When accelerating, to about 40 MPH, the car will shift from 4th to 5th gear. Anywhere between 38 MPH and 42 MPH while in 5th gear, assuming I am giving the car a constant amount of gas with the pedal, it will do this. I will be bringing my car in NEXT Wednesday (03/16/11). They could take it sooner, but I need a loaner car, and that is the first available opening with a loaner. I swear I'm about to print out this thread and make them read it haha... I'll report back with any updates.

[rune]

rune - According to my CPO paperwork (certified last month/ about 700 miles ago), they changed the tranny fluid, and also changed the oil/filter.

I called the dealer today, because it is acting up again as of today (Monday). It is less severe than the video I posted, but the car still makes awful noises when the rpm's move. I have figured out at least one way to replicate the issue most of the time >>> When accelerating, to about 40 MPH, the car will shift from 4th to 5th gear. Anywhere between 38 MPH and 42 MPH while in 5th gear, assuming I am giving the car a constant amount of gas with the pedal, it will do this. I will be bringing my car in NEXT Wednesday (03/16/11). They could take it sooner, but I need a loaner car, and that is the first available opening with a loaner. I swear I'm about to print out this thread and make them read it haha... I'll report back with any updates.

Today driving to work ca 50-60 km/h and around 1500RPM on 5th gear i feel the exhaust working and i see the variation on the tacho meter up/down with ca 200RPM.
i hope we can find out what is going on, it should NOT be like this. I have an appointment next tuesday to change my parts(PCV,DV,N249 valve) and check oil level on tranny. Oil level is very important for the tranny to work as it should.
But, it seems to be from 3th gear up i have this problem and when engine is in startup fase.When warm as said earlier it is fine.
i will keep you updated if anything happens.

Good luck :-)

[rune]

Hi Wild

About 2 weeks ago my B7 strangely over revved a few times while driving at various speeds, the once it under revved, strange!!! anyways took it back to Audi, they have replaced the Inlet manifold as the there was a leak from the seal (complete unit replaced), this seems to have done the trick, or at least no more symptoms.

Mac

I find your replacment of the intake manifold interesting. I have searched and found out that this is a part that often fails.
Looks like my car has some codes, DTC 08200 and 12600. This relates to intake manifold flap motor.

Did you have same symtoms like me and wildcat have ?

wildcat: Are you sure you have no codes ?

[wildcat333]

wildcat: Are you sure you have no codes ?

As far as codes... I do not have any check engine or idiot lights on my dash. I don't have a vag-com unit, so I'm not sure about anything more in depth. My rpm's are still doing their same ol' routine (as described above). I would like them to replace as many parts as possible to fix this. 8 days till I drop it off at the dealer...

[rune]

As far as codes... I do not have any check engine or idiot lights on my dash. I don't have a vag-com unit, so I'm not sure about anything more in depth. My rpm's are still doing their same ol' routine (as described above). I would like them to replace as many parts as possible to fix this. 8 days till I drop it off at the dealer...

Do you have any updates ?

[wildcat333]

Do you have any updates ?

I took the car to the dealership on 03/16/11. The Audi Service guy called me yesterday and told me the following:

They drove the car on a test drive. They agree with me, and admit there is in fact an issue. They found a code indicating a fuel pressure issue. They replaced the fuel pressure sensor. This did not fix the issue. They opened a ticket with Audi Corporate, and were waiting to hear back from the corporate service guy before they move forward.

I really do not know what that means, or if that's a good or bad thing. All I know is I am glad it is certified pre-owned, and glad that they don't think I'm crazy. At least it will eventually get fixed fairly soon I imagine.

Also, I get to drive this for my loaner car > 2011 Audi Q5, literally brand-new with 7 (yes, seven) miles on it. Insane. It has the 2.0T engine, with the Premium Plus package. The thing is real nice. I am not normally comfortable with SUV's, or being high above the road like that, but it is very smooth and pretty baller-status I have to say.





>
>

Does anyone have any guesses now as to what the problem might be? I'll be sure to report back once I know more info.

[rune]

I took the car to the dealership on 03/16/11. The Audi Service guy called me yesterday and told me the following:

They drove the car on a test drive. They agree with me, and admit there is in fact an issue. They found a code indicating a fuel pressure issue. They replaced the fuel pressure sensor. This did not fix the issue. They opened a ticket with Audi Corporate, and were waiting to hear back from the corporate service guy before they move forward.


I really do not know what that means, or if that's a good or bad thing. All I know is I am glad it is certified pre-owned, and glad that they don't think I'm crazy. At least it will eventually get fixed fairly soon I imagine.

Also, I get to drive this for my loaner car > 2011 Audi Q5, literally brand-new with 7 (yes, seven) miles on it. Insane. It has the 2.0T engine, with the Premium Plus package. The thing is real nice. I am not normally comfortable with SUV's, or being high above the road like that, but it is very smooth and pretty baller-status I have to say.





>
>

Does anyone have any guesses now as to what the problem might be? I'll be sure to report back once I know more info.

Nice Q5,

I got my car back today after changing DV,PCV,N249 valve and fuel filter. Did check oil level in the tranny and seems to be good. They also cleaned the throttle body and did a adaption.
Will report back when i have time to do a test drive, hopefully tomorrow.

[wildcat333]

Nice Q5,

I got my car back today after changing DV,PCV,N249 valve and fuel filter. Did check oil level in the tranny and seems to be good. They also cleaned the throttle body and did a adaption.
Will report back when i have time to do a test drive, hopefully tomorrow.

Sounds good, rune.

Update: I just got a call from the Audi Service guy at the dealership. They did some more tests with the VAG computer unit, and it appears the torque converter is not locking up like it should. Apparently this is not a mechanical problem, but something more of a software problem. They will be keeping the car over the weekend, and they hope that Audi Corporate will send them a software update for my car on Monday.

[rune]

Sounds good, rune.

Update: I just got a call from the Audi Service guy at the dealership. They did some more tests with the VAG computer unit, and it appears the torque converter is not locking up like it should. Apparently this is not a mechanical problem, but something more of a software problem. They will be keeping the car over the weekend, and they hope that Audi Corporate will send them a software update for my car on Monday.

Hi Wild

After testing my car today, my car is the same as before.

I hope you find out on monday. Did they say if the software update was for the transmission module or engine module ?

Hope this will be solved, and i will sleep better at nights

[wildcat333]

Update:

I just got a call from Audi Service. They did a transmission software update today, which did not solve the problem. Audi Corporate is ordering the dealer to replace the torque converter. It has been ordered, and will arrive at the shop on 03/23/11. I looked it up online, and it appears this repair will take approx 10-15 hours to complete - sounds pretty intense. Has anyone ever had their torque converter repaired? Is this a good thing, or should I now be worried about the fate of my transmission in general? Ughhh. At least they are still working on it I guess. Tomorrow I will have had my car one month exactly :/

[rune]

Update:

I just got a call from Audi Service. They did a transmission software update today, which did not solve the problem. Audi Corporate is ordering the dealer to replace the torque converter. It has been ordered, and will arrive at the shop on 03/23/11. I looked it up online, and it appears this repair will take approx 10-15 hours to complete - sounds pretty intense. Has anyone ever had their torque converter repaired? Is this a good thing, or should I now be worried about the fate of my transmission in general? Ughhh. At least they are still working on it I guess. Tomorrow I will have had my car one month exactly :/

Hi wild

This is not good news. You are lucky you have guarantee. The TC is a very expensive part. I had a feeling it could be the TC doing this, but hoped not. We will see after you have changed TC,then we will know for sure. I will wait your report on this before i do anything more on mine.

good luck,

[fly300kts]

Well well, torque converter...... Never heard about any failure and again, that brings the discussion towards the tranny fluid level.

Phil

[bbimmer]

very timely thread. My 2006 A4 Avant 2.0 started doing this 2 days ago. Noticed that at a steady throttle, going about 35mph, rpms fluctuate ever so slightly. Noticable on the tach and can also feel a slight pulsating in the engine. Has definitely happened while car is cold. Will have to check and see about when warm. Regular maintenance/fluid checks always followed/performed. 55k miles on car. Out of warranty unfortunately.

[airbornerifleman]

subscribed!

[wildcat333]

Just a brief update: The TC has not yet arrived from Audi Parts. They said "it is currently somewhere over the Atlantic." They expect the part to arrive this Friday (03/25/11). I will be out town until Monday, but I'll report back with updates then.

[wildcat333]

UPDATE:

I picked up my car today. The newly installed torque converter did the trick! They installed it, did a 60 mile road test, checked the computer, and everything was good. I drove it 1.5 hours home tonight with all sorts of driving (city driving, highway, and sporty acceleration) and it is driving perfectly. The RPM's no longer fluctuate where it used to (always when shifting from 4th to 5th around 40 mph) in drive.

It had been in the shop for almost two weeks, which sucked. BUT it made me truly appreciate the car again. It is so much better than the Q5 loaner in my opinion.

Rune, and any others with similar issues: I hope this thread helped. Feel free to message me or reply to this thread for any questions. I wish you the best of luck with your repairs.

NEW TORQUE CONVERTER FTW!!! CPO FTW!!!

Now time for the mods listed in my signature!!! WINNING!!!

[rune]

UPDATE:

I picked up my car today. The newly installed torque converter did the trick! They installed it, did a 60 mile road test, checked the computer, and everything was good. I drove it 1.5 hours home tonight with all sorts of driving (city driving, highway, and sporty acceleration) and it is driving perfectly. The RPM's no longer fluctuate where it used to (always when shifting from 4th to 5th around 40 mph) in drive.

It had been in the shop for almost two weeks, which sucked. BUT it made me truly appreciate the car again. It is so much better than the Q5 loaner in my opinion.

Rune, and any others with similar issues: I hope this thread helped. Feel free to message me or reply to this thread for any questions. I wish you the best of luck with your repairs.

NEW TORQUE CONVERTER FTW!!! CPO FTW!!!

Now time for the mods listed in my signature!!! WINNING!!!

Good to hear you have your car fixed.

Did they say what inside the TC was failing ? What the cause was ?

[airbornerifleman]

Thanks for the info OP

[wildcat333]

Good to hear you have your car fixed.

Did they say what inside the TC was failing ? What the cause was ?

Hey, rune - they didn't specifically say what inside the TC was failing. I read the entire service printout sheet they gave me. It just sounded to me like it was the last possible thing that could be wrong with the car, and they just had to replace it. It's gross though that I had become so used to hearing the RPM fluctuation noise, that I almost still expect to hear a f***ed up noise still, haha! I really hope you figure out your issue. I'm also subscribed to this thread, so I'll keep up with your progress if you decide to post updates here. Good luck.