Hi
'94 Grand Prix 3.1L 197K idles fine but recently has begun to "stumble" (cough and hesitate?) on acceleration. If I floor it- it will respond but still stumbles a bit. I recently did have the engine light come on. I won't ask about pulling the code because I already know it can't be done on this car without a scanner (OBD1-OBD2 transition car).
Last year I had the opposite problem- a rough idle. I eventually fixed that by replacing the digital egr ($40 junkyard as opposed to $250 @ Azone!) During my attempts to fix the idle problem I did the following: New plugs, New plug wires, new pcv, cleaned throttle plate, new air filter, new fuel filter.
Based on what I did already within the last year, what is likely causing the stumbling now? I am guessing: o2 sensors, MAF sensor or IAC?
The scanning situation on this car sucks. It costs $70 locally just to have that done. Autozone cannot scan this car- they have told me and have even tried but all they use is a jumper key which is a waste of time.
Thanks for any suggestions!