Hello, I have a 1990 Pontiac Grand Prix with 3.1 and about 200k miles
(odometer hasn't worked in about 6 years). I recently put the ol' girl back
on the road after sitting for 2 years and I'm running into a poor running
condition. I had driven this car for 3 days since putting it back on the
road and put hundreds of miles on it. The problem started when I went to
start it one day. I cranked it for a split second (long enough for it to
start usually) and the engine just fired once and sputtered. (Kind of
sounded like it fired the engine backward... I only bumped the starter). So
I just tried to start 'er again.
Then it would just crank. I tested for spark and there was none. I have a
spare computer, which I swapped to no avail. I went and picked up an
ignition module the next day and decided to try to start it again before
tearing into the car.. It started up but acted like it had a bad misfire. I
assumed (oops) it was the ignition module so I changed it. Still had a
misfire. I tested for spark at all coil packs and all seems good.
I figured I'd scan the computer for codes; it can't hurt. Well code 33
popped up. So I checked the vacuum line and wire connection at the MAP
sensor. All seemed OK so I changed out the MAP sensor. Well it's still
running like crap. It's like it's misfiring. Fairly regular misfire, but it
seems more like a 'blubbering' from too much fuel. Smells like it out the
exhaust too. If I can get it to idle it really chugs out the exhaust.
Why else would it pull a code for the MAP sensor? Could the poor running
condition mimic the readings of a failing MAP sensor to the computer? How
can I test the MAP sensor? (Although I'm fairly certain the new one is OK)
Any other ideas? Any help would be appreciated.