well, as posted above, i suggest running your car for error codes before doing anything else. you can do it with a paperclip and your DLC. If you dont know how tell me and ill post up some directions later, or search the forum and see if you can find it, its in several threads on the board.
Also i agree that it very well may be the ICM, its located under your distributor rotor, its very easy to change and not very expensive, i think 50 bucks.
your tranny may have some miles, but a worn out auto tranny wouldnt be causing your problems in all likelyhood. an auto thats giving up the ghost tends to alow higher rpm operation, not bogged down low speed operation.
regarding your non factory air cleaner assembly, if you want to fix it, a cheap and effective method is to hit up the junk yard and score the nessesary parts from a doner car. other than that you can get the parts from the GM dealership and probly
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