Well Like the subject says my car continues to have a rough and possibly low idle problem that I can't seem to fix. Here is what I have replaced and fixed so far:

Optispark(went bad a few months back)
Plug Wires(Msd 8.5's)
Cleaned IAC sensor(it was pretty dirty)
Cleaned TB(it had a little bit of carbon build up)

When car is warmed up the tach reads right on the 500rpm mark, and the car shakes a bit and you can literally see the tach move up and down a hair when looking closely. It is a A4 car by the way with a descreened MAF, could this cause any of these problems, or could if be maybe plugs, O2 sensors, or any other sensor, please any help would be appreciated....Thanks in advance.

 

check the : EGR, TPS & MAP sensor. Clean the EGR no matter what it looks like. check fuel pressure with regulator disconnected and connected. Also look, listen or use liquid to help find vacuum leaks. Have the MAF checked or swap with a friend.

Replace: routine maintenance items that have not been changed in the last 50000 like O2's and plugs. ONLY USE OEM. Not sure why you would change distributor and wires but not plugs. Don't forget the fuel filter.

Have the injectors professionally cleaned.


Cheap easy stuff to do.

 

check the MAF, and I would put the screen back in as well. Having that out has been known to cause problems in some vehicles, and the performance difference is minimal if any at all for a basically stock car. Also, clean it with a spray electronics cleaner, that may help.

 

I have exactly the same problem. Changed fuel filter - no help, so waiting for other ideas.