a4 quattro 2.8 rough idle problem help please!!!!
 

ok i have had this car for 5 months now and it was perfect and still drives perfectly fine but when i am sitting at idle it shakes a little like sputtering, i can put my hand in front of the muffler and feel it sputtering. cleaned the throttle body b/c i read that is the number one cause of rough idle, but it didn't work. so i went and got the obd scan and got codes p0056, p0156, and p0340...did lots of research and i don't think its the 1st 2 (o2 sensor) but the 3rd says camshaft position sensor intake circuit bank 1, from what i've read that could mean the cam position sensor or the crank position sensor or just poor electrical connection. the thing is i don't have the money to play the guessing game to figure out which one it is. so anybody ever have this problem that could help me out?

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

I have a 2001 a6 with the same exact problems. We have changed the cam shaft and crank sensors and neither corrected the problem. Have you had any luck?

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

nope, but we also had code for o2 sensor pop up and we talked to someone who said that is the problem. i will let u know if it fixes the problem when we change it

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

We also threw an O2 sensor code, but we were told that that would not cause our problem. So far we have changed all the spark plugs and vacuum tubing too. : / it runs absolutely great, as long as you are moving. Are you changing the O2 sensors soon?

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

hopefully this weekend..will let u know. we didn't think it could be o2 sensors at first but a friend of ours said he had the same problem on his a6 and it turned out to be o2, and he also said if you don't fix it, it can mess up the cat! so that will be the next thing we do, then the timing because we have no idea when the last time it was changed was

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

I had the timing belt and all that changed at around 100000 miles. After i got your reply about the O2 sensors I did a little more searching about it and it can cause that. Odd that the dealership was not concerned about those codes. We do most of our own work, but not when it comes to the timing and luckily we have a good friend that works there that helps us out ALOT!! I will keep you posted with updates as well, hopefully between the two of us we can figure this out without going broke!

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

Good news usher found out what was wrong. It was a cam timing variator. Bad news, 1200 to fix it. I am lucky that we have a friend at the dealership and they did it for $300. It is almost back together. I hope the o2 sensors solve your problem. Post and let me know, I still have two throwing codes that are next to be fixed.

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

I spoke too soon. When the regulator broke pieces of plastic went into my motor and bent three valves. So it still isn't fixed and will cost a lot more to fix.

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

Ok so it is all fixed now. Six bent valves and three bent lifters later. But, I didn't fix any o2 sensors and now the check engine light isn't on at all. I guess it can be a dummy code. Did you get yours fixed?

Re: a4 quattro 2.8 rough idle problem help please!!!!
 

what is the cam timing variator, i tried to look it up but i can't find anything on it. i'm not going to the stealership my husband fixes our cars but this is our first audi and it's a lot more complicated. so wait was it the cam timing that was making it idle rough or the bent valves?