1990 Grand Am Jumpy start to occasional stalling

Hi,
I'm new on here, but scanning through a few posts I'm thinking there may be someone here who could help.

I have a 1990 Grand AM SE (Quad 4) with about 80k miles on it. First, about 6 months ago when the "service engine soon" lite came on, I went to the shop, they had to hook it up to the computer, then they wound up replacing the spark plugs and oxygen sensor. Around that time (shortly before I think) I was having a little bit of rocky starts. It got worse for a few weeks. I would start and it would just shake rattle and roll like it was gonna stall but would usually be okay. Then as I would go slowly over speedbumps in my apartment complex it would stall sometimes. Othertimes it would almost stall but wouldn't completely. Important to note is that this only happened upon start up when the car had been sitting for a number of hours. I work from home so it will sometimes site for even a day or two. But as soon as I've hit normal roads it has no problem starting up anytime I stop at a store or anything.

So it went on for a few weeks and I brought it back after like the fifth stall in my apartment complex and they said they can't figure out the problem.. so I'd have to leave it there so they could start it up cold in the morning to see it stall. I was like... "Well, it doesn't always do it though.. most of the time it will just be shakey and only stalls when I'm slowing near speedbumps (again within minutes of the first "start up" of the day.) So I said screw that basically.

Strangly it seemed much better throughout the winter months. But lately it's been shakey again. Could be my imagination though, but I feel like if I crank my air (not AC, just hair hot or cool) it levels it out.

Any help would be appreciated. Thanks!

I can't believe no one has even a guess at this? I was surprised given the dozens of responses to an array of questions on here that I haven't even had one yet.... Please help if you can anyone. Thanks!

Just a guess, but try testing your coil packs, one might be weak, and also check your plug wires.

Just a guess, but try testing your coil packs, one might be weak, and also check your plug wires.

Thanks. I'll have to have it looked at.. don't even know what "coil packs" are.... With regard the my wires, I think they should be fine, because I belive those were replaced when my plugs and oxygen sensor were (from earlier part of my post)... Not sure, but either way they were checked, and I would assume they were checked when I went back talking about this current problem. But I can ask them to check that too...

What about battery/alternator stuff? I had problems on my old Corolla with that, but it was mostly caused by my high powered stereo system being too much for them to handle... and it seemed to react different than what I'm having now... but it was a manual too so it was different, cuz I could rev when power seemed to be going. Anyway, I only ask because I read a somewhat similar problem on here somewhere, and people were telling him to have alternator and battery checked.

Let me know what you think. Thanks again.

If you suspect your alternator or battery, have autozone test them, they do it for free. It's possible that your battery is tired, or your alternator is not putting out enough power at idle. Also check your battery cables at the battery, starter and ground, something might be loose or dirty.

If you suspect your alternator or battery, have autozone test them, they do it for free. It's possible that your battery is tired, or your alternator is not putting out enough power at idle. Also check your battery cables at the battery, starter and ground, something might be loose or dirty.

Cool, thanks for the tips man... I'll check all those things out. Just really trying to see if it is something that will progressively get worse really... Like I said, once I get going I'm fine.. Just when the car has sat for a while... And I didn't want to wake up one day 6 months from now and have it not starting and realize my engine was seriously screwed somehow, and I had ignored it. Anyway, thanks again.