Help!?

[swrt83]

Yo guys,

So just the past couple days I noticed that my car is kicking while cruising on the highway. The first day I noticed this, it was in the AM and raining. It didn't occur the rest of the day while driving and I chalked it up to my worn tires lack of grip in the wet. The next morning it was still kicking, and got noticeably worse when I hit some highway traffic. I don't hit the throttle heavy and it was really stuttering when I would get around the 2k-3k RPM range. My 3.0 only has 55,5xx mi on it.

Fearing the worst, obviously, I called the dealer and figured it was either the tranny (6-spd) or Quattro going bad :( I scanned as soon as I got to work, had no vag errors except a COMPLETELY random air-bag code: 01366 - Opened Due to Crash Signal : 36-10 - Open Circuit - Intermittent. So I got it in the dealer a few hrs later, and assuming they found nothing, wanted me to drive it with a tech in the car to see if I could replicate it.

As soon as we pulled out of the lot, BAM, stuttering (god only knows how he didn't catch this?). Anyway, the tech thought maybe it was related to the throttle body, and said sometimes they act up when dirty. I also mentioned I had been having a very minor rough idle the past month.

More waiting in the dealer, and they get back to me stating they replaced coilpacks in cylinders 2/3 because of some mistimings, and did a 'throttle adaptation'. I was semi-happy, and left after paying the CPO co-pay (makes you feel like you're at the doctors office). As soon as I pull out.. you got it, more bucking.

So if I haven't lost you at this point, WTF is a throttle adaptation and does anyone have any remote idea what could be wrong with the car? I appreciate you taking the time to read this story and hope you can help me out!

[dougyfresh]

'throttle adaptation' is required anytime the ECU is removed from the vehicle or if you pull the throttle body out of the car to clean it. It is also required after disconnecting the battery. The throttle body on our vehicles (B6 A4 1.8 & 3.0) is electronically controlled. No cables from the gas pedal to the TB. Its all electronic. The throttle body servo (what actuates the plate inside the TB) needs to be re-calibrated whenever there is a disruption in the circuit (battery, ecu removal, etc..). Here is some more reading about TBA (throttle body alignment/adaptation) http://wiki.ross-tech.com/index.php/...Alignment_(TBA)

I'm glad to hear they did this for you. Did they also clean the TB out like you suggested?

The rough idle may be contributed due to cracked and/or broken vacuum lines. The easiest way to figure that out is to start at your intake manifold and do a visual inspection of all the small lines (about 4-5mm in diameter). The factory lines are cloth covered and tend to break around the mileage your car has. They can not take the heat after many miles and years. I recommend replacement of them with 100% silicon lines. Do a search for 'vacuum' in this Tech Forum and you'll fine a few posts about it.

[swrt83]

Hey fresh thx for gettin back so quickly, I wasn't sure if anybody would really have any input with this sorta thing. The tech told me it was all electronic, and I actually found that same link yesterday, but it didn't help me too much when I attempted to self-diagnose the situation. He said that depending on what he found when he opened the TB up, he would either have to do an adaptation, clean it a little, or maybe just replace it all together. So I wasn't entirely sure what he did, since I didn't get a chance to speak with him after the car was finished.

It didn't fix the problem though, and I scheduled the car to go back in on the 28th. I'm not sure if they'll need to clean it real good, or replace the whole thing. Any idea what causes this electrical 'disruption' ? I just picked up a VAG and have been playing with the car.. did the seatbelt chime, key-fob windows, and 1 touch lock/unlock. Also did the central locking at 10mph and adjusted the coming home feature length from 30 secs to 20 secs.. but that was AFTER I noticed the TB problem. So I wouldn't think it was me playing around with the car?? I was just extremely worried it was the tranny or the AWD system since I've only had the car for about 9 months!

Oh and regarding the idle, I'll have to mention the vacuum lines when it goes back in!

[dougyfresh]

I reread the OP... Please help define 'bucking'. What exactly are you feeling?

The car is still doing this now, after your first trip to the dealer? To the same extent?

[swrt83]

While cruising on the highway and going over any sort of road deviation from flat pavement, it would 'kick' on me.. almost like a quick lag or stutter and this would happen while I was ever so slightly on the throttle around 2K RPMs no matter what gear I'm in. The adaptation helped a bit, so it isn't quite to the same extent, but it's still noticeable..

EDIT: Someone suggested it was maybe a bad tank of gas, but I don't feel it in the engine, esp while heavy throttle is applied. It's in the wheels that I feel it.

[dougyfresh]

So, you feel it in the wheels and suspension? Not the engine or trans / drivetrain?


'kick' as in split second hesitation? Or as in your wheels are actually hopping over the bad road terrain... aka: catching air.

[swrt83]

Let me clarify.. I don't feel any 'knock' from the engine which makes me want to rule out a bad tank of gas. Plus I'd imagine if it were engine knock from bad fuel, it would get alot worse if I tried to stomp on it. It feels more like the drivetrain then it does wheel slip or 'getting air' b/c we're talking about ANY sort of deviation, not just large bumps. So the tires are always making contact with the pavement while this is happening. And yes, we're talking about that split second hesitation, and then the car feels like it will 'throw' itself forward for a split second.

[bavaria75]

He got a manual, could the clutch be done??? But this would be odd on cruising speed.
You metioned it happens only over bumps or rough road? Not on a flat even road?

[dougyfresh]

I thought of a clutch but if the clutch was slipping you'd notice it specifically when flooring the car and trying to accelerate quickly.


Are you getting any misfire codes? You could throw a misfire code without throwing a CEL. It will also tell you which cylinder is misfiring. A misfire would cause a split second hesitation. The primary causes of a misfire on our vehicles are the coil packs (but you've had 2 out of 6 replaced so far).

[swrt83]

No codes thrown.. don't get me wrong, it isn't just bumps and uneven (rough) pavement. I have noticed it does it BARELY while on completely flat highway. Could this be as simple as dirty injectors? It seems to be happening while i'm easy on the throttle, like hardly touching it, not when i'm hard on the accelerator

[bavaria75]

Hmm just want to through a few more thoughts in here:
As mentioned Vac lines
Fuel filter?
Fuel pump, maybe more under acceleration again.
Oil filled up nicely. If not your engine would properly be dead by now, but you never now.

[swrt83]

Fuel filter just replaced about 1500 miles ago. Serviced about 2.5 months ago. I have a feeling its either a bad or dirty TB. How would vacuum lines contribute? The more I drive it the more I notice it kicks on me while I'm ever so slightly on the accelerator pedal..

[bavaria75]

Vacuum lines control various throotles on your engine. You should notice it if the engine runs not as smooth or your gas milage goes south. Your engine will properly still run with a hole in a vac leak, but just not as smooth.

[swrt83]

I wanted to update this, so people with similar situations will have it to fall back on as reference. Just got it back from the dealer - no issues anymore.

After they replaced the 2 coilpacks for cylinders 2 and 5 and did a TB adaptation, it still had problems. So they held onto the car the whole day for the most recent visit. They logged the timings of the camshafts, sure enough they were off. However, they weren't getting any error codes. The lead tech replaced a timing sensor for camshaft 2, and this fixed the problem.

For some unknown reason (they always are), the mechanism that triggers the error to the ECU was completely OFF, which is why they weren't getting an error for camshaft two (only getting a code that said camshaft 2 adjustment). They turned it on before they replaced the sensor and BAM - error code thrown, so it was misfiring.

It now runs smooth and I'm a happy camper!

[04QuattroTurbo]

Does this work?:
CLick

[dougyfresh]

I wanted to update this, so people with similar situations will have it to fall back on as reference. Just got it back from the dealer - no issues anymore.

After they replaced the 2 coilpacks for cylinders 2 and 5 and did a TB adaptation, it still had problems. So they held onto the car the whole day for the most recent visit. They logged the timings of the camshafts, sure enough they were off. However, they weren't getting any error codes. The lead tech replaced a timing sensor for camshaft 2, and this fixed the problem.

For some unknown reason (they always are), the mechanism that triggers the error to the ECU was completely OFF, which is why they weren't getting an error for camshaft two (only getting a code that said camshaft 2 adjustment). They turned it on before they replaced the sensor and BAM - error code thrown, so it was misfiring.

It now runs smooth and I'm a happy camper!

Glad to hear you guys found the root cause.

Which cylinder head? Driver or Passenger? I know the 2002 3.0s had some issues with the cam lobes grinding off.

Did they pull the valve covers to do a visual on your heads and cams?

When did you have your timing belt replaced last?

Just curious as to why you were throwing a cam code outside of "the sensor plain old just failed"