Backstory: I have a 2002 Cavalier with the 2.2 ecotec engine. A while back it lost power and was only running on two cylinders. I pretty much knew it was ignition related so I removed the coil-pack on top of the engine and removed the plugs for inspection. Two of the four plugs were worn so badly that they couldn't fire. There wasn't much left for the electrode to spark to, unless it was sparking to the top of the piston. I couldn't believe the car was even running with these plugs. With only $100 in my hand I purchased 4 new plugs and a new after market coil-pack to be on the safe side. I decided to use my old ICM. One of the new plugs was improperly gapped so in an attempt to get the gap in tolerance, I accidentally broke off the very tip of the electrode. I bent the cathode back in tolerance and "went with it". The car fired right up and ran perfect.... for about 2 months. Now I have a mystery.

The car runs fine while cruising above 1000 rpms but as soon as you come to a stop it starts missing and stumbling. It idles a bit low though and has an occasional miss at cold idle. It gets worse if the cooling fan is on or the A/C. When the fan kicks on the car immediately stumbles and all the lights go dim as if the battery was low. I'm thinking that its only due to the 400-500 idle the car currently has, added with the random miss fire or stumble.

I just knew this problem was the ICM because that was the only thing I didn't replace and many places I searched online said this is the most common cause of miss fires and P300 codes. I bought a new "cheap" ICM that didn't fix my issue. Swapping my coil-pack out with the old one didn't change anything. Swapping out the ICM with the old one didn't change anything either. I thought it might be that one plug that I broke so I bought 4 more new plugs and installed them which still didn't change anything. This leads me to believe that the only thing my car needed was spark plugs in the first place, and maybe this is true but this seems different altogether. I have searched everywhere on many forums and elsewhere and found only 1 youtube video that shows a car like mine doing the exact same thing and they said it was the MAP sensor. I have one on order but I'm not thinking that is my problem either because:

Old coilpack with new ICM gives me best results. Still misses and stumbles but not as bad as other combinations.

New coilpack with old OR new ICM (don't matter) stumbles worse, misses more at idle

Old coilpack with old ICM is better but not as good as what the new ICM does even though it throws a "check engine" and "trac off' lights..

The old parts are original equipment, the new parts are aftermarket and weird named.

If my MAP was bad, why all the variation with the different ignition components? Unless someone has a different idea I'm going to install the MAP and see what that does and if that don't work I may try to find O.E. Coils and ICM.

Some of the variation in the ignition components may be due to the plug boots not being shoved up against the coils completely. I'm hoping that it was just my error because if so it puts more burden on the MAP being the culprit.

at the 0.33 mark you can see a little dip in the rpms. My car does this "dip" every 4 or 5 seconds.

I'm doubting it jumped time or my cat is clogged as I have experience with these issues on other vehicles. While searching for vacuum leaks nothing was discovered. Anything else thinking MAP sensor?

Clean the throttle body.

The "little dip" every few seconds isn't the air conditioning compressor, is it?

a dip in the rpms when fan or compressor turns on is normal... but this is ever few seconds....

Throttle body? maybe a leaking gasket but im sure its fine... MAP sensor coming tomorrow.. .ill go from there... im 85 percent positive it is map or a bad "new" ICM now... just curious if anyone has had this exact same issue... OR if anyone has gotten a bad "new" ICM

Right, and if the charge gets low sometimes they will engage every few seconds, that'* why I'm asking. Does this happen when the HVAC controls are completely off and you are watching the compressor clutch?

Map came in today. I thought for sure it was the problem... but no.. its doing same thing... P0300 code stored, now no check engine light but "trac off" comes on.. stays a while then goes off only to return shortly after.

This miss or stumble at idle happens no matter if ac is on or off, but is usually worse when the cooling fan is on.

Now im thinking its the cheap ICM i got off amazon for $30 bucks because the old ICM runs with the same stumble and miss but much worse. The best combo so far is the Old coilpack with the new ICM.
The engine runs with the same problem no matter what coils or ICM I use just a matter of how bad it shows its self. Old ICM could be bad, The new cheap ICM may be bad as well, just not as bad as the old one.

Going to be a little while until I can afford an AC Delco part, few weeks at least.. Will keep everyone updated till then... if any other ideas come to mind, shoot them at me please.