ok, first week of january i put my longtube headers on (and plugs), ran open headers as my every day car for about 3-4 weeks, ses light came on regularly but no problems that i could tell, had a burnt wire so i changed my wires. 4 months later, ive got my Y pipe on etc, and under acceleration not necisarily hard, it jerks like maybe lack of fuel etc, just jerks (stumbles) for fraction of second, but does it often under hard acceleration) and normaly after it does that SES light comes on (still does it with light on) but dont do it AT all when the car is cold, not at operating temp, i changed o2 sensor, then went out to test it, now im jerking jumping etc etc etc when car wamrs up and i mean its bad so bad i cant move it over 15-20 mph, car jerks back fires etc , i put clutch in and rev up, i had trouble getting it to over 3k rpms, it woudl jump backfire pop go down up etc like crazy...then ses light comes on, and it runs like it did b4, just the stutter now and then....so i change Fuel filter next, didnt do it, then MAP sensor, didtn do it, then coil pack, didnt do it, then MAF didnt do it , then PCV valve, didnt do it....im sure im forgetting something.....during the header install i broke the little shroud for the plug to latch onto off the temp gauge on the driv side of block, but i glued it back on and its still on there good (duno if that might have smoethin to do with it or not) ANY help apreciated, also had it scaned and "no trouble codes" showed...(that was b4 it started doin the crazy bad non driveable problem)

 

Try LT1 tech and if that don't work post this in the advanced tech forum.