Stuttering problems won't go away!

[sigamated]

I own a 2006 Audi A4 2.0T Quattro, 48,000 miles and I have spent more time in the shop this year than driving!

The car basically works fine for a week or so and then the whole car starts shaking and stuttering! Really bad in idle mode but also occurs when accelerating. I always use 91 grade gasoline or higher (94 sometimes).

This will be my 5th trip and 3rd mechanic this year! Here is a list of everything that has been done thus far, based on the check engine light error codes:

- New PCV Valve and gasket
- New Air Filter
- All new spark plugs (4)
- Oil change and filter
- Replaced all 4 ignition coils for the 3rd time!!!!
- New Fuel Filter
- New fuel pump
- New Battery
- New turbo cut-off valve


It now runs worse than ever!!!!!! Please help~

[AKO]

When does the stuttering occur? during idle?

[sigamated]

When does the stuttering occur? during idle?

During idle and acceleration. It's intermittent. Comes and goes

[AKO]

Im having the same issue i think on acceleration! it also comes and goes like you said

[LoKisSpYdR]

Carbon cleaning time!

The way that our cars are setup stock, "normal driving" will create lots of carbon build-up. These cars NEED to be driven hard. The more you're boosting, the less you'll have positive crank pressure forcing all that gunk into the head via our brilliant PCV setup.

[airbornerifleman]

My engine stumbles at idle when I first start it up, the hose that attaches to the vacuum pump is loose and leaks and rattles, causing my engine to stumble. Once the car is warmed up, or I start driving the stumbling subsides.
OP, you need to check for mis-fires with vag com when the shaking occurs. You might have a bad fuel injector. I changed the #2 fuel injector once at 80,000KM and recently at 155,000KM.

[midnight407]

only 48k mi on an 06?!

[sigamated]

That's correct 48,850 to be exact! I'm guessing it could be a million and 1 different things but it seems as though the fuel line needs flushing or something

[Kewk]

When mine was acting the way you described it was a bad coil. Once that was replaced it didn't jerk around like that but it started going into limp mode at high RPM's. I took it to audi and they had to replace a cam.

[TFSI]

Here is a list of everything that has been done thus far, based on the check engine light error codes:

- New PCV Valve and gasket
- New Air Filter
- All new spark plugs (4)
- Oil change and filter
- Replaced all 4 ignition coils for the 3rd time!!!!
- New Fuel Filter
- New fuel pump
- New Battery
- New turbo cut-off valve


It now runs worse than ever!!!!!! Please help~

I'm not completely sure what the problem is.

One thing I'm thinking about is that your mechanic did replace whole lot of parts that were not necessary. Not sure if he is willing to help out, but that's just a lot of money.

[bman005]

Sounds like either a carboning or injector issue to me

[80sGuy]

I own a 2006 Audi A4 2.0T Quattro, 48,000 miles and I have spent more time in the shop this year than driving!

The car basically works fine for a week or so and then the whole car starts shaking and stuttering! Really bad in idle mode but also occurs when accelerating. I always use 91 grade gasoline or higher (94 sometimes).

This will be my 5th trip and 3rd mechanic this year! Here is a list of everything that has been done thus far, based on the check engine light error codes:

- New PCV Valve and gasket
- New Air Filter
- All new spark plugs (4)
- Oil change and filter
- Replaced all 4 ignition coils for the 3rd time!!!!
- New Fuel Filter
- New fuel pump
- New Battery
- New turbo cut-off valve


It now runs worse than ever!!!!!! Please help~Were they factory OEM Audi parts? Did you bring it to a dealer or to some random mechanic shop? If not, double check the part numbers and make sure they are the right ones for your B7. Our cars can be extremely picky on parts not being factory OEM. Also, before you spend more money, it doesn't hurt to swap out some of these items yourself:

*N80 Valve (www.europaparts.com/purge-valve-06e906517a.html/)
*Diverter Valve (http://www.europaparts.com/diverter-valve-06h145710d.html/) (previous models 2006, up to 2008) are fitted with a 'C' diaphragm-type, if broken, you'll need to get this one)

Also, I think it's time you visit a different mechanic/shop.


edit: didn't see that you've replaced the fuel filter there.

[eyesolution]

Carbon cleaning time!

The way that our cars are setup stock, "normal driving" will create lots of carbon build-up. These cars NEED to be driven hard. The more you're boosting, the less you'll have positive crank pressure forcing all that gunk into the head via our brilliant PCV setup.

X2

I had the same problem and took it to the dealer. Everything checked out ok except that small misfire that i was having(I can't remember the reading they gave me). Every morning the car would shake like crazy. After basically diagnosing the problem with them we came to the conclusion that I should clean my intake valves and it fixed it! The dealer didnt charge me anything since they said i helped them diagnose it HA! saved $120 for diagnostic [:D]

[sigamated]

Thanks everyone. I should note that a few of the items I mentioned are not related but the problem is, every time it does this the error code reads something new. There has to be a root problem.

[LoKisSpYdR]

Carbon buildup.

[Jhad]

Unplug your MAF and drive it. See if the idle is better.

I was getting rough idle when I would start my car, car was shaking and would stall out. It eventually got worse, and I was losing power and choking into limp mode at wot and/or around 4000 rpm.

I had new coils, plugs, vcg, cc, new lpfp, cf, hpfp, and fuel filter, all within 5,000 miles. So the last thing I checked was my MAF. Sure enough, a new one fixed my problem. Only throwing that out there for you- it's worth a try

[crumple]

I had the same problem, is your car hard to start after you refuel? If so it could be a bad n80 valve which was the case for me. replaced it for $15 in like 15 mins

[doughboy17]

ThThThThThThThat's all folks.
ThThThThat's all folks.
ThThThat's all folks.
That's all folks.

Stuttering problem solved.

[Toasted Coastie]

ThThThThThThThat's all folks.
ThThThThat's all folks.
ThThThat's all folks.
That's all folks.

Stuttering problem solved.

So, what solved it?

sent from the T3

[Operator]

doughboy was making a joke. The OP hasn't said the car is fixed yet.

[Toasted Coastie]

doughboy was making a joke. The OP hasn't said the car is fixed yet.

Ha!

sent from the T3

[toml]

I've got a 2006 tip/quatro with just 36,000 miles...my suggestion is to clean the throttle body. If they get gummed up they will cause erratic idle and throttle response. Once that is done do a throttle body realignmment. Good luck

[JackIT]

I think I have the same problem. The car is a 2007 A4 2.0T Quattro Tiptronic with 64K miles. Mods: APR Stage 2, Rev D Diverter

The stuttering problem began about 4 weeks ago and has intermittently reappeared since then. The first time it happened was within minutes of the start of my early morning 30 mile commute, going steadily about 25mph i could feel the car stumbling and requiring more throttle to maintain the speed, then I felt the car fall flat on it's face almost as if the brakes had been applied or I had been rear ended, the rest of my commute was uneventful, except for the fact that it felt like the car was in limp mode, low boost and slow acceleration.

The problem has reoccurred about 5 times over the course of 4 weeks and 1,500 miles. typically the problem manifests upon mild or light acceleration, you can feel the car stumble, misfire and struggle to accelerate. Then, without doing anything on my end, the car returns to "normal" albeit a limp mode, which seems to clear up after a day or two of driving.

I should also mention that 90% of my driving is done on the highway, with very little stop and go and average speeds of ~ 75mph.

I've taken the car to German auto repair shop, where they checked the codes. The codes showed misfires on all cylinders and unaccounted for air past the MAF. They checked for vacuum leaks (found and repaired a small one), ran some more tests, cleared the codes and declared the car fixed. It ran fine for about 5 days and the stuttering reappeared.

I really don't know what to do with it, so any advice would be appreciated.

[eyesolution]

Carbon build up
MAF sensor
Coil Packs

[Jhad]

Jackit- if your coils and plugs are good, pcv is good, vc is good, no vac leaks, and your maf is good. I would venture a guess that its your thrust sensor. should be covered under warranty- if you hate your stealership (like me) and want to diy its only $45

[airbornerifleman]

^ If you already checked the coil packs spark plugs and did a cold engine compression test, the problem is most likely a combination of carbon build up and/or clogged injector(s).
Since you are getting misfires in all cyls, it might be you CPs shitting the bed.

[JackIT]

Jackit- if your coils and plugs are good, pcv is good, vc is good, no vac leaks, and your maf is good. I would venture a guess that its your thrust sensor. should be covered under warranty- if you hate your stealership (like me) and want to diy its only $45

I changed the plugs about 5K miles ago, the mechanic tested the PCV system and said it was good, they also tested and repaired a small vac leak.


Is there a way to test the coils, maf and thrust sensor? The problem is very intermittent and impossible to reproduce, so it's difficult to troubleshoot.

[JackIT]

^ If you already checked the coil packs spark plugs and did a cold engine compression test, the problem is most likely a combination of carbon build up and/or clogged injector(s).
Since you are getting misfires in all cyls, it might be you CPs shitting the bed.

if the injectors were clogged, would the problem be fairly consistent? That fact that the car drives normally with great acceleration the vast majority of the time, makes me think it's not the injectors.

[eyesolution]

Jackit- if your coils and plugs are good, pcv is good, vc is good, no vac leaks, and your maf is good. I would venture a guess that its your thrust sensor. should be covered under warranty- if you hate your stealership (like me) and want to diy its only $45

adding to this the intake flap motor is under warranty too. if dealer is going in there you should get them to replace that too.

[Jhad]

if the injectors were clogged, would the problem be fairly consistent? That fact that the car drives normally with great acceleration the vast majority of the time, makes me think it's not the injectors.

thats why i mentioned the thrust sensor. Mine would acceleratefine at anything <1/2 throttle. WOT would bog it down, and sometimes while keeping an even speed- my rpm's would fluctuate (not due to a bad tc). Then it would occasionally surge from limp mode to normal- it was driving me effing crazy. I had a new apr pump- but they installed the old thrust sensor from my stock pump so I never thought it was my thrust sensor (had a shop put the pump on so I could get flashed apr 2+, one of the few times I didnt work on the car myself).

Are you going into limp mode at about 4000 -4500 rpms? How is your idle at cold start? rough? ever have it stall out shortly after starting? What i was told/researched was that the sensor was giving bad readings, and ecu thought my car was starving of fuel putting me immediately into limp mode. I was getting all diffent codes- underboost/overboost, p310b, p0087, etc. I would clear them, and then hit 4000 rpms in 3rd or 4th gear to trigger the cel. My maf/map/hpfp/lpfp were all new. It was never a consistent code which led me to believe that it was wiring or a sensor issue.

Sorry for the long post, and of course- your results may vary, and there are many other variables to account for. But if all of your maintenance is up to date, and you are having an inconsistent cut in power, its worth a shot.

[JackIT]

Are you going into limp mode at about 4000 -4500 rpms? How is your idle at cold start? rough? ever have it stall out shortly after starting? What i was told/researched was that the sensor was giving bad readings, and ecu thought my car was starving of fuel putting me immediately into limp mode. I was getting all diffent codes- underboost/overboost, p310b, p0087, etc. I would clear them, and then hit 4000 rpms in 3rd or 4th gear to trigger the cel. My maf/map/hpfp/lpfp were all new. It was never a consistent code which led me to believe that it was wiring or a sensor issue.

Sorry for the long post, and of course- your results may vary, and there are many other variables to account for. But if all of your maintenance is up to date, and you are having an inconsistent cut in power, its worth a shot.

Thanks for the details.


I really haven't pinned down when it goes into limp mode, but 4K seems about right. The cold idle at start is a little rough but not bad and the RPMs hold steady. The car has never stalled, though it did come close the very first time this happened.

at $45 buck, it's probably worth replacing

thanks.

[jmaneyapanda]

I would look into the intake manifold motor. Mine shit the bed, and I had horrific misfire and stutter at anything over 0 pounds boost.

[SoonerE39]

only 48k mi on an 06?!

I'm only at 31000 on my 2007. Its a Cabriolet which helps explain lower miles (not great for cross country road trips or running errands to Home Depot)