Hello,

So when I had my 2006 Audi A6 3.2L V6 FSI scanned with a VCDS system a bunch of codes came up, including misfires in cylinders 2 and 6 (low voltage), O2 sensor B1 S1, intake manifold stuck open on both banks and an evap leak code.
I have since then fixed all of them along with an oil change, new ignition coils, new O2 sensor, and the CEL went away as of today 0 codes in the system.
Now I have had choppy idle on cold starts and hesitation when accelerating especially from gears 2 to 3 for a while now but I was told they were related to all these codes and would go away once everything is fixed. Its been almost two weeks and although there are no codes and no CEL illuminated the car is still choppy on idle and is very hesitant when accelerating it has gotten worse for sure.

I have attached youtube link to show the hesitation when accelerating from a stop (the noise is from the rain this was during a rain day): At about 36 second mark in the video, I start making the left turn and the car jerks back as soon as I press the throttle, and at times when accelerating the car jolts from the back to the front while the RPM needle is going up and down. Even on the highway cruising at about 60 70 the car feels like it's slowing down on its own but then there is a heavy jolt from the back to the front and it keeps going. When moving from gear 2 to gear 3 the RPM reaches almost 3.2k to 4 at times on the gauge and sometimes I have to manually change gears because of the loud engine noise.

I have also attached a link where you can hear my A6 on a cold start: At about 20 second mark, the sound of the engine suddenly rises then falls and then rises again, the pattern continues for almost 1 minute before settling down. The RPM needle doesn't rise or fall along with the engine idle sound it only falls to about 700-800 after around 1 minute when the engine is settled (1:04 in the video). I also start the car with the AC off so that isn't causing the choppy idle.

I don't know what else it can be, no vacuum leaks were found, I sprayed all the hoses with soapy water and let the car idle for a while.
I'm coming to this forum as a last resort, the mechanic said it's the flex pipe on the driver's side that's making the car hesitate and idle choppy about 500 to 700 for the job he said he is going to need to weld stuff together.

 

 

My '06 C6 3.2 has 194k miles on it now, & I'm putting the effort in to keep going with it.
My goal is 250k miles(400k km).
Right now, I'm working through a trans valve body/solenoid issue. So far, my engines upper tensioners are holding up well, but I have had to change out the hpfp & a cam sensor. The oil leaks always frustrate me!
However, it's easier, cheaper & more fun to deal woth $1-2k/yr of repairs & maintenance on this car than replace it.
I love the capabilities of this car much more than i would of anything more reliable & pedestrian.

 

My '06 C6 3.2 has 194k miles on it now, & I'm putting the effort in to keep going with it.
My goal is 250k miles(400k km).
Right now, I'm working through a trans valve body/solenoid issue. So far, my engines upper tensioners are holding up well, but I have had to change out the hpfp & a cam sensor. The oil leaks always frustrate me!
However, it's easier, cheaper & more fun to deal woth $1-2k/yr of repairs & maintenance on this car than replace it. I do 95% of the labor myself. I only farm out to my indy the work I don't feel like doing, which isn't very much. I knew what I was getting into when I got this car at 151k miles.
I love the capabilities of this car much more than i would of anything more reliable & pedestrian.

 

Made an account just to tell you that I struggled with the same exact problem on my '05 A6 and it turned out to be a dirty throttle body. Especially given that this happens more when the car is cold then settles as it warms up. This happens because the grime and dirt in the throttle body loosens up as the car gets to operating temperature and the butterfly valve in the TB starts moving more smoothly.

Take off the TB and spray thoroughly with TB cleaner. Use a microfiber towel to clean it out. Make sure to open the flap by hand and clean both the edges of the flap and the inside of the TB where the flap sits when it is closed.

Also, a lot of people say you *need* to do a TB adaptation after doing this but I've had no issues without it.

 

LarryJa,
What made you have to replace the hpfp and camshaft sensor? Codes telling you they were bad or just symptoms? I have occasional random misfires on all cylinders and I am looking at these 2 items. No codes (other then the Evap Exhaust Leak that I have always had) pointing to anything for me. Thanks.

 

akingzkid, I had codes to lead me to each.
The hpfp gave me an fp regulator short to (+), & the cam sensor gave me an "implausible signal" code.

 

Thanks. I once had a camshaft sensor implausible signal code (G163) when I first got the car but I think once I cleared all of the codes with my Xtool VAG401, most of them never came back (including the camshaft sensor code). That is unless I don't remember exactly where to go to find it. This would be in the form of a DTC code and not a fault right? Thanks.

 

Try the cheapest and easiest thing first. Like you were thinking of doing it, fill up your fuel tank, add strong treatment to fuel and drive hard until you run out of gas to clean up injectors, fuel lines and the engine system.
If you feel improvement, repeat the process to further clean the system.
Second, I would suspect a clogged fuel filter.
Third, fuel pump.
It could also well be a dirty throttle body like bxpaisan said.

 

Bhavik, I too had this problem a while back. The throttle body cleaning did the trick even though it looked like an insignificant amount of soot around the throttle plate. I used orange hand cleaner to break up all the oil and soot, then rinsed it with mass air flow cleaner.