...Okay, it's in a N-body, not a J-body, but hopefully you guys can look past that and help me out! Hah.

'88 Grand Am 2.0 Turbo, 5-speed. Car had a slightly choppy idle ever since I've owned it. About a month ago it developed a random miss at light throttle. About two weeks ago it started having a random miss at all times, all rpm, any throttle position, etc. Threw the standard tune-up parts at it (that it probably needed anyway), plugs gapped to .030, wires, cap & rotor, fuel filter, o2 sensor, switched to another ignition coil I had lying around, no luck. Even had the timing belt off and re-timed the engine just to be sure.

I have access to all the old GM service info at school, so just for the heck of it I looked up the procedure to time the engine. It tells me to jump pins A & B in the ALDL connector while adjusting timing. So guess what, whenever I jump those pins it runs fine. Well, almost fine, still a slight miss at light throttle, but MUCH better. That leads me to believe that it's some sort of sensor/engine control module issue. The only other issue is that the timing seems to jump around whenever I have the light on it.. it could be the fact that I'm using a crappy sub-$20 Harbor Freight timing light, but thought mention it just to cover all my bases.

Any input? I have a 2.0T Sunbird that I can swap parts with if needed.. which I'm probably going to start doing as soon as I hit send. Thanks guys.

Welll... as of the last couple of hours here's what else I've changed: MAP sensor, IAT sensor, boost sensor, ICM. Still no luck. Only sensors left that I can think of would be the throttle position and the knock sensor. Any clues to where the knock sensors are on these motors?

Knock sensor should be on the back of the block but don't swear to it's exact location.I would recommend checking the egr valve and the ohm resistance on your injectors.I'd have to research my believe or not old grand am book I have to see if it specifies where on the back of the block for the knock sensor.It is pretty big unlike a oil pressure sender.

Found the knock sensor, it's on the back side of the engine above the oil pan.

Now this stupid thing is messing with me. Took it to the track Friday night, had the pins jumped, car was running fine, I even ran my best quarter mile in that car ever. Made the almost 4 hour round trip without a hiccup. I go out today and start it up, it's running terrible, almost sounds like it's off time or something.

I'm stumped.

Too tired to elaborate or think on the issue.But It is cool for the run times story.Let me get some sleep as I am wiped out.

No worries, appreciate the help! I have trouble finding people that still know how these cars work.. haha.

I am a first gen owner and that grand am is not too far off in the general works of how things operate.I am def tired but what wires did you bypass.My grand am manual is in the other room and do not want to dig it out soo late.Just tell me what you did so when I get this manual I can try and make some recommends on the next steps of things to check.I tell ya a 13 hour day just wipes you out.