About a week ago you guys helped me figure out that I had a bad coil pack which was causing misfiring at high rpm. Well, it'* back. Just to recap, I put in MSD coil packs and about two weeks later one of them must have gone bad because as soon as I switched them back to the coil packs that were on before, (stock coil packs), it was running fine. Well, now a week after doing that, it'* misfiring again. Not as bad as it was before, but still very noticeable at high rpm. I don't want to put spend the money on another set of coil packs if I'm just going to kill them in two weeks. Any ideas what could be causing this? I'm thinking my next step will be to try the msd coil packs again, (a new set), along with ZZP wires and some Autolite 104'* and hope this problem goes away for good.

Try and clean your coils....

https://www.gmforum.com/t282147/

Replaced the coil packs, put on zzp wires and replaced my ac delco iridium plugs with autolite 104'*, also cleaned the contacts since I was already in there (thanks for posting the link, and for the tutorial Dan). Once again the car is running like a champ (a pretty damn quick champ :P).

On a side note, I did notice that the spark plugs had what resembled glazing (yellowish, orange coating) which had built up again since the last cleaning only 2 weeks ago. I'm thinking I may have outgrown those plugs, and it'* a good thing Dan suggested the Autolite'*. That still doesn't explain why it started running fine after switching back to stock coil packs though, unless the problems were related somehow. Anyways, I'm crossing my fingers hoping that is the end of that problem.