Pontiac Repair: 1996 Sunfire, gm dealer, injector cleaner

Question
Help!!!  My sunfire, which I absolutely love..or did until recently has begun to have problems intermittently.  It will run fine and then sputter and try to staul.  When this first happened, there was actually a fire in my exhaust.  Plugs, wires, O2 censor, fuel filter have all been changed.  Lucas injector cleaner has been added.  Nothing has helped.  Someone suggested that one of the coil packs may be bad.  My son seems to feel that this isn't the case as there is a steady and constant spark.  The catalytic converer has been bypassed as well and that wasn't the problem.  Any advice or information you could offer would be greatly appreciated.  It is a 2.2 litre/

Answer
Hey Ella:

It could be a number of things. For the most part these cars run pretty good and don't have many stalling issues to speak of. Has an service engine light come on? Does this have an automatic transmission? Does it stall or try to stall when you are coming to a stop? Does it stall like a manual transmission when you forget to step on the clutch?? or does it try to stall or act up while driving down the road? If it's when slowing down and it feels like it's gonna stall Ala manual transmission If this has a 3 speed transmission unplug the electrical connect or the front of the transmission and drive it to see if it stops doing it. If it's stalling while driving it could be a fuel pump issue. I have seen all kinds of goofy stuff happen with this car when it has ECM "computer" issues. that car had a recall for the ECM to put a cover over it to keep the water from getting into the computer if that was never done that would be the very first thing I would have checked. Just call any GM dealer and give them the VIN # of your car and they can tell you if this has been done before. If you not the original owner you wouldn't know if it were to have been done before. Just a few things to look at before you go throwing more parts at this car and not fixing it. Good luck :)