Hello all,
My 2003 with a 3.0 all of the sudden yesterday started to idle badly and die with no restart. It started after it sat for a few minutes, but the idle would be terrible, the tach indicates near stall and jumps up to approx 4000 rpm, up and down continuously. When I put it in reverse, it would do the same thing, causing the car to surge, I had to keep pressure on the brake to control it. In drive, it had loss of power, very noticeable and surges still. I also notice a smell from the tailpipe that resembles too rich a fuel mixture. I just had all the coil packs replaced by Audi about 3 months ago.
Any ideas what this is?
Thank you for your help.

 

Start checking, replace the MAF sensor
Message #11 below link
https://www.audiforums.com/forum/sho...35#post1318135

 

I removed the MAF sensor and cleaned it best I could, (I don't have any rubbing alcohol right now) and reinstalled it. It seams somewhat better but it still wants to stall when I come to a stop and the RPM's still jump up and down. I disconnected it entirely and still the same effect. I also got a lot of fuel smoke at start up and at idle, I can smell and see it.
Hmmm, any more ideas to check into o is this still probably the #1 cause?
Thank you again

 

A bad fuel pressure regulator would cause either lack of fuel pressure or excessive pressure. If
I would say check its vacuum hose first, but since it dumps too much fuel - based on your smoke description - then probably the vacuum isn't the problem as the spring still pushes/opens the fuel regulating diaphragm.

 

The suddenness of it all points to an electrical component. The electrical components that control idle are the first suspects. The idle air control valve is the first with throttle position sensor next. Then go to mixture control sensors such as the MAF sensor and the O2 sensors. Query the ECU for pending codes just in case a sensor is reporting in with a problem. Another possible suspect is a vacuum leak in the intake system. Start looking for broken hoses and fittings or hoses disconnected. The crankcase ventilation system can get plugged, pull it apart and look inside.

 

I agree with Jeff, the O2 sensor is bad.... its reading that it needs to kick more gas in, floods it at idle, although if you try to light your exhaust.