I have the 2.8 A4Q. I changed my oil yesterday after doing the sea foam in a vacuum hose (brake booster). Then after that I drove my car around letting the oil run through the car. I stoped at a red light and it droped down to around 50 RPM and shot back up to normal idle. I was woundering if anyone one knew what would cause this help would be thanked. I changed my oil today (next day) and it still does it. It has no codes. It also has a huge new oil filter (bigger than the one that was on the car before the first oil change). I added engough oil to compensate for the bigger filter.

 

oil filter has nothing to do with it, accelerate to 3k rpm and hold for 3 mins this should reset the ECU then take it for a drive

 

yep first resest ecu. if that doesn't fix it..... if it's an older 2.8 like mine is like a 96, then it could be the ICV, Idle Control Valve. When i bought mine it had a malfunctioning icv and the owner thought it was a big problem with the engine. It's not at all, all you have to do is clean it out with carb cleaner becaues gunk gets built up in it. Its a last resort though, cuase it take like 3 hours to do. Find the write up on it if you think it's your problem.

 

Drive 40 miles until the ecu resets completely.

Then see where its at.

 

You might need a throttle body adjustment.

 

thanks for all the help i will try all your ideas

 

I was thinking wouldnt reseting the ecu get rid of the misaligned headlight "code"

And my car doesnt do it anymore

 

eeeee these new cars get my head up my ar2e what will the add to the computer/ ECU to confuse us misaligned headlight "code" new one to me