Engine runs rough at all speeds. No engine codes showing up. Changed spark plugs and wires problem still there. Engine is not overheating. Idle seems to be high around 1000 rpm. Kind of runs as if there is a vacuum leak but so far I can't find a leak. Engine seems to start ok. Problem just appeared. I don't hear and odd engine knocks or noises other than some valve tapping noises, but that has been there since I bought the car.
Engine running rough on 1995 Oldsmobile Cutlass Supreme
by Randy95 in Proctorville, OH on December 03, 2010
ANSWER by DaveJM , December 03, 2010
Sounds like a vacuum leak or a sticking idle speed control motor. You have the right idea. Keep looking for any disconnected hoses, air tube cracks, etc....