Some questions:
At idle, does your idle stay stable at about 7 or 800 RPM or does it drop when you put it in gear and add accessories?
How smooth is the idle in neutral with no accessories?
Have you checked the throttle position sensor to make sure it's triggering "idle" when the car is at idle? (see bentleys)
Classic idle roughness is typically due to a vacuum leak somewhere in the system. Even a very small one. Have you really carefully checked:
- ICV lines and clamps
- 3 mm vac lines from manifold to FPR and valve cover vent
- AFM to throttle body hose and clamps
- valve cover vent line and clamps
- charcoal cannister vent line under manifold
- brake booster lines, check valve (cracks) and clamps
Did I say "careful"? Yes - I believe I did. Get anal as all heck and be sure to look *really carefully* and replace anything suspect. Be sure to dig around and really check the connections to the manifold. Yes, the ones that are hard to see and a pain-in-the-ass to check.
If that all looks good then try:
- spraying out the ICV with sensor safe carb cleaner
- new plugs, cap rotor
- adjust valves to about .012 or .013 cold
- check engine temp sensor to ensure it works to spec (bentleys will advise)
- carefully inspect plug wires and replace if old
Tramlining...sounds like you've done most of the typical suspension work. Could be your rim tire setup. My setup with 16"'s tramlined like heck with worn Yoko AVS db tires. Completely stopped with new Bridgestones. Any way you might try another rim tire setup to find out if it's the car or the tires?
Hope this helps,
Jeff
Last edited by Jeff N.; 10-31-2004 at 12:37 PM.
Bellevue WA
90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
86 Porsche 951 - Track Toy