car still not running right

[firebirdTA20]

my 94 trans am has been down for about 2 months now. i have been doing everything i can to fix it and try to figure out what is wrong with it im out of ideas and pretty much out of money. Basically what its doing is it is running rough at idle, backfires, when you step on the gas the whole car shakes then it smoothes out beyond a certain point, and it smells pretty rich. My friend and i have done lots of diagnostics i have replaced lots of parts that could have been it but none of them have fixed it. I replaced my MAP/MAT sensor, IAT sensor, Oxygen sensor that was reading slow on the scanner anyways, cap and rotor, distributor, spark plugs, wires, fuel filter, EGR valve, and checked vacuum lines and compression checked cylinders 1,3,5,7. Im out of ideas and running out of money i need help. I brought it to my buddys shop he works at harvey cadillac, and we hooked my car up to the scope to try to look around a little better since you cant really pull anything out of the OBD 1 setup, and we found the my car is only runngin on 6 cylinders at a time at idle. Everytime you turn the car on the cylinders that had no spark change, started out that cylinders 6 + 8 werent sparking, then we turned it off started it back up and it was 6+2 not firing, then we did the same again and it switched to cylinders 4+5. the only things i can think of now would be computer issue, or a defective cap and rotor. I really need help if anyone has an idea let me know, thanks.

[s.reef]

I think Kolin (tastyzr1) had a simlar problem forgot what it was though....

[Formula Z]

damn man, sounds like you have tried a lot, at least things id recommend. hopefully someone on here has some advice or knowledge on the issue. good luck and if you need any help let me know.

[s.reef]

Oh yea...it was a stripped opti shaft or something like that.

[firebirdTA20]

that could be, im definatly thinking that my problem is either something with the ignition or the computer

[ITSSLOW]

Oh yea...it was a stripped opti shaft or something like that.

Yup, that was Kolin's problem on his 93 TA

[s.reef]

Sounds like the same symptoms as kolins

[DRYSUMP]

hey the splineshaft on the back of my opti was stripped out and was casuing a misfire in my engine...have fun finding one.....they r dealer parts only search the net for one tho

[archemedes]

before buying a new one, try swapping out the pcm with a known good one (have someone near with the same part number?)