Have a 96 lumina, 3100 runs horrible. Have replced fuel pump, fuel filter, plugs, wires, and coils. Car idles rough, stalls, over revs (rarely), sputters, misfires and tranny shifts very hard on first to second shift. Not worried about tranny but figured id mention incase it could somehow be related. Car also sets, multiple cylnder misfire, number 2 cylnder misfire, and Auxilary emissions control codes. Im almost out of ideas so if anyone can help i would appreciate it.

TIA

I had a 96 with a 3.1 that had a problem with a bad fuel injector...You didn't mention checking changing or cleaning any of them. My Chevy dealer told me that fuel injector problems were the #1 most frequent problem in their shop. Replacing any of the injectors requires removing the upper intake manifold. This was 4 years ago and prior to replacing the injector I was able to squeeze periods of normal operation out of it by running injector cleaner through the fuel system. The Chevron Brand cleaner works the best I think it's called Techtron...there's a lot of crappy cleaners on the market if you don't use a good one it won't help much. Eventually I had to install a new injector. If you want to do it yourself it is do-able just a lot of disassembly
to get to it.


Spit

I did run some fuel injection cleaner in it and didnt seem to do much but as you said there are alot of junk cleaners out there so maybe the stuff i used was garbege. Fuel injectors were something i was leaning towards next but i have no idea as to wear to start on troubleshooting them. I guess i could just take them all out and clean all of them. Is there any easy way of testing the injectors?

Also forgot to add in my original post i was setting a code before i replaced the fuel pump, "bank 2 to lean" i believe is what it was. But have not had that code come back since replacing the fuel pump.

I did run some fuel injection cleaner in it and didnt seem to do much but as you said there are alot of junk cleaners out there so maybe the stuff i used was garbege. Fuel injectors were something i was leaning towards next but i have no idea as to wear to start on troubleshooting them. I guess i could just take them all out and clean all of them. Is there any easy way of testing the injectors?

Also forgot to add in my original post i was setting a code before i replaced the fuel pump, "bank 2 to lean" i believe is what it was. But have not had that code come back since replacing the fuel pump.wow... before you do anything else, test, test, test!

Things to test:

Fuel pressure...at the injector rail, not only on prime, but also during run...
once you have your basic pressure, unplug the regualator, see if the pressure changes...

Spark... now i under stand it runs... but test each individual wire..<---best method is an inductive timing light... rev it up when testing each wire, see if the light skips...

If you have spark at each plug and it doesnt skip, pull the plugs and make sure they have fuel burn (i.e. look like they have fired fuel) and are not wet, if they are wet, one of five problems...ecm not telling moduel to fire, moduel not firing, bad coil, bad wire, bad plug...

Pull the plugs, check their gap against what the catalyst says... if they look like they have fired fuel, pull the wire for that cyl, let it run for one minute, shut car off, pull the plug, if it is not wet, the "injector" for that cyl is not firing...

Check for vacuum leaks, most common place for your car is from the intake to the p.c.v. valve (positive crankcase ventilation) <-its a hard plastic line that sometimes cracks...(right where you cant see it)...

^^^time not money^^^

If you go through all those steps and that doesn't fix it, find a good mechanic, that can run a data stream, and knows how to interpert it...

I am willing to bet its gonna be something very simple, if your still having problems after all that............. see signature below... hope that helps loosenut...