Idle speed
 

I have a '90 I just tried to emissions test. Problem is... it won't idle low enough. It goes down to about 1150 to 1200 rpms. It needs to be under 1100 rpms (although it seems low enough for me). As far as any mods... (to the engine) it has a DRM prom in it, RC injectors, minor port to injector housing and plenum and a Flowmaster cat back. What could be causing this? Any suggestions? Is there (hopefully) an easy way to adjust idle speed? PS, I finally got around to replacing the injectors, coil packs, and plug wires... At 70K miles this thing RIPS! :-D Thanks, pfastzr1 [/i]

1) Make sure you don't have carbon buildup at the throttle blades.
2) Check your throttle position sensor (tps)
3) Check for vacuum leak.