2009 Quattro TFSI - Stuttering at 2500-4000 RPMs, Gears 2-5

[maybenot]

As the title says I am having issues with stuttering. It started about a week ago and has slowly gotten a little worse. It feels like a transmission issue or maybe a fuel issue, just want to see if anyone has experienced this. I have researched a lot on the topic in multiple forums, but none seem to match my issue 100%. This video is very similar to what I am experiencing, the RPM's drop exactly like that. Just seems that mine is in the 2500-4000 RPM range, in multiple gears and will stutter 1-3 times in the RPM range sometimes. https://youtu.be/RYX-H4Dy0nU

Info on car: 2009 A4 2.0TFSI, CAEB, 6 Speed Auto, Quattro, 164,xxx miles.

Things I've noticed:
-Does not do it nearly as bad (sometimes not at all) when cold compared to operating temp.
-Only does it when I push the accelerator ~30%-65%. Anything more it accelerates just fine. Anything less is just fine as well.
-More noticeable and harsher in 3rd and 4th but will occasionally feel it in 2nd, 6th, and 5th.
-Shifts, Idles, revs in neutral, takes off and starts perfect. No issues in any of these.
-Tach will show that it will drop 100-200 rpms before quickly returning.
-Zero Codes (Granted, I do not have VAGCOM. If I truly need it, I will buy it but if I am being honest, I don't think I will have this car next year.)
-2 or 3 times it jerked pretty bad when it acted up, almost like dropping a clutch kind of a jerk. Which is why I am thinking it might be a transmission issue.

Other current issue(s) with the car (In case these matter)
-Steering wheel shake from 65-78 mph. Been fighting this for a long time and it won't go away. If anyone can help with this, it would be much appreciated as well. Sometimes it doesn't shake at these speeds and sometimes it vibrates my hands off.
-Anything over 78 mph, steering wheel shake disappears and the whole car will vibrate, especially the driver seat. Nothing vicious, it kind of just vibrates like a phone. Again, any help would be appreciated on this issue.
-Leaks coolant and I cannot track it down to save my life. It's not consuming coolant since it leaks out of the skid plate though. Coolant leak happened suspiciously next to the stuttering issue I am having but I don't think it is relevant.
-Leaks a small amount of oil out of the upper timing cover, specifically out of the bottom of the camshaft adjuster magnet gasket.

Repairs that I have done (Just in case these matter as well)
-(~5,000 and ~10,000 miles ago) Upper timing cover and cam adjuster magnet with all accompanying gaskets. All new and redone twice. Still leaks, wahoo.
-(~10,000 miles ago) New front suspension (control arms, struts, etc.) excluding tie rods. This due to a steering wheel shake at highway speeds that will not go away, every part mitigates it but will not kill it. Tie rods are next.
-(~7,500 miles ago) New CV Axles. Due to the above issue.
-(~15,000 miles ago) Timing overhaul (guides, chains, bolts, tensioner, timing cover, etc.) due to scares of the catastrophic timing tensioner. Did spark plugs and coolant flush as well.
-(~30,000 miles ago) New fluid in front and rear diffs
-(~40,000 miles ago) New Front Wheel Bearings
-(over 50,000 miles ago) Alternator
-Many, many, many, alignments and balances because of the steering issue.
-Synthetic oil changes every 5,000.


After all of that word vomit and what is most likely pointless information, I will continue with more searching on what I should start with and will start testing parts as well. I am just hoping that someone has had this issue and knows how to fix it. As always, thank you for any replies or suggestions and if someone out there also has an answer to the steering shake issue let me know as well, in the next few days I will post a separate thread on this issue though. I love this car, but these issues are driving me insane so please help before I send it off a cliff!

[MongoMcG]

Re; Shakes
I don't have Audi specific advice for the vibration, but I've run into similar issues with my old cars, the Austin Healey especially. Your shake sounds like it is being induced by vibrations (likely in the front suspension) combining with resonant frequencies in the car. When there is discord between the resonant frequencies of the car and the suspension vibration, the peaks and troughs of the waves are added or subtracted to/from each other, thus increasing or decreasing the resulting shake. Usually the problem comes down to worn or failing bushings in the control arms, a bad wheel balance or a broken suspension component. I replaced all of the rubber in the front suspension on the big Healey, and it now drives like a vintage racing car. On the Audi's it is a lot easier to replace the whole control arm rather than the bushing.

Another suggestion: flush and fill the power steering fluid and add a triboceramic additive (RVS Tech makes one) to freshen up seals and lubricate. This is a pretty easy DIY. Probably won't help the steering wheel shake, but with 165K on the clock, it's time for fresh fluid. If you use the triboceramic additive: it is thick and will not will not easily pass through the screen inside the power steering fluid reservoir, so pre mix the additive with 1/2 liter of PS fluid. The total PS fluid used should be about 1 liter.

Re: the RPM drop
I think the ECU is introducing that behavior (not mechanical) because it is seeing something it doesn't like at that moment. That is to say, the symptom (RPM drop) is not mechanically derived, but rather it is software driven. However, the crux of the problem that causes the ECU to trim the juice might be mechanical. If you just want to pull codes (if any are present) you can use a cheap OBD II device instead of VCDS - just make sure it is compatible with the Audi CAN-BUS. My gut tells me the waste gate or the diverter valve on your turbo is toast. Also possible - the fuel is reading too rich, bad gasoline, clogged cat, bad O2 sensor, many more.

I'll leave with this...
Considering where in the RPM range your symptoms appear, if you have the plastic intake manifold, it could be the intake manifold flapper system. The system uses vacuum and an actuator to open an close flaps in the intake manifold to change the direction and velocity of air flowing into the cylinders, and the system is a known failure point on these engines. Will mainly toss codes P2004, P2005 and/or P2070 iirc.

[maybenot]

Thank you very much for the reply, on the shaking, I agree on the resonant frequencies. I did get all of the control arms replaced in the front and I have checked the rear control arms and they seem just fine, tight with no movement, no torn or worn-out bushings. Front Tie rods are next all though those feel tight as well so I am not sure if it will help but I am hoping that it will solve the steering wheel and vibration issues. If not, back to the drawing board. I will say, after driving today I found that when I steer from center to left or right, I can feel (not hear) a slight "clunk", like something is getting hit or engaged when I make the slightest turn of the wheel. Making me think the tie rods are going out. Maybe the rack and pinion? I forgot to mention but I have checked the parts of the steering shaft I can see, there is not up and down movement and there is a very slight rotational movement but when I rotate it, I can see that it is turning my tie rods slightly. There is no play between the joints of the steering shaft either. Is there any part of the steering system that could potentially cause this "clunk?"

Good point on the power steering, I will get some of that on order and do it even if it's just to have fresh fluid that keeps seals alive.

Now onto the engine issue, it felt much worse today, hardly accelerating past 3k rpms and I finally got it to throw a code. P0303, cylinder 3 misfire. Spark plugs are new, so I am just going to switch coil 3 with coil 1 and swap spark plug 3 with spark plug 4. If I get a different code, I will know whether its the coil or spark plug. If none of those, then I am going to check vacuum, fuel and anything that could involve ignition.

Again, thanks on all the advice.

[MongoMcG]

I've never been in an Audi steering rack job, but all racks can clunk. It's usually something to do with the spool valve or steering rack pre-load. I can't go into any specifics because I don't know the Audi racks, but these two items might be a good starting point. Here's a VW centered video - no idea if any procedures presented here are silly.


Here a steering rack adjustment on a TT:
https://www.ttforum.co.uk/threads/st...ustment.95471/

[Theiceman]

the bonus infamous for the ujoint in the steering shaft to clunk. many get replaced . guys have reported success spraying the crap out of it with deep creep.



Sent from my SM-G973W using Audizine Forum mobile app

[MongoMcG]

the bonus infamous for the ujoint in the steering shaft to clunk. many get replaced . guys have reported success spraying the crap out of it with deep creep.



Sent from my SM-G973W using Audizine Forum mobile app

The lower steering shaft u-joint is another known failure point. My brain skipped over the part where you typed that you "can feel but not hear" the clunk, so Iceman is sending you in the right direction. For a couple of years I've been spraying Tri-Flow lubricant on the u-joint as part of spring and fall maintenance. Tri-Flow is actually the chain lubricant for my bicycle, but it has been working okay on that u-joint. Unfortunately the u-joint cannot be replaced, requiring instead replacement of the whole lower steering shaft. It's an easy gig - two bolts and the rubber boot - but the shaft is 500 bucks.

[redrackham17]

the bonus infamous for the ujoint in the steering shaft to clunk. many get replaced . guys have reported success spraying the crap out of it with deep creep.



Sent from my SM-G973W using Audizine Forum mobile app

Yep that's me. I am guys. Any time when there is a lot of salt on the road or the car has been up on a lift, that U joint makes low speed turns feel like hell. What you gotta do is grease it when the wheel is straight, turn it to the right, grease again, turn to the left, grease again, and then drive in a empty parking lot at low speed but locking the wheel right to left like 5 times. My friends tell me I look like a little kid learning how to drive but it works every time and beats getting a new U-joint.

[maybenot]

Thanks all for the advice. I'll look into the steering shaft and rack closer. I drive on salted roads a lot so I would not be surprised if that was my issue as well.

Just an update on the engine stuttering. Unfortunately, even after switching the coil and spark plug to different cylinders and clearing codes, I am still getting a cylinder 3 misfire. Although I have to force the code out of the car. It will stutter and jerk, but it won't give me a code until it sees fit. I don't know if that has much to do with the issue but there's that. I have a compression tester and a coil tester on the way but in the meantime is there anything else I can check? I'll continue searching forums to see what I can check for though. I also have one of those fixd obd2 scanners that can tell my live data from sensors, not sure if it will help but I will see if anything jumps out at me when it starts acting up. Thanks again.

[redrackham17]

Thanks all for the advice. I'll look into the steering shaft and rack closer. I drive on salted roads a lot so I would not be surprised if that was my issue as well.

Just an update on the engine stuttering. Unfortunately, even after switching the coil and spark plug to different cylinders and clearing codes, I am still getting a cylinder 3 misfire. Although I have to force the code out of the car. It will stutter and jerk, but it won't give me a code until it sees fit. I don't know if that has much to do with the issue but there's that. I have a compression tester and a coil tester on the way but in the meantime is there anything else I can check? I'll continue searching forums to see what I can check for though. I also have one of those fixd obd2 scanners that can tell my live data from sensors, not sure if it will help but I will see if anything jumps out at me when it starts acting up. Thanks again.

Use your OBD2 scanner and look at the fuel trim. Also, look at how much timing adjustment is going on. Otherwise, you probably gotta wait for that compression tester.