Car is spitting and acting up...

ok i have a 98 firebird. ive put a v-force muffler on it and i had to replace the catalytic converter.now months later this is what its doing = it started acting like it was spitting when i would accelerate real fast as if it had water in it. well so i put heat in it which absorbs water. well i ran that down to Empty. still does it. i have used premium gas every since. I can like accelerate at a pace and it wont do it but if i hit the gas to hard then it will act like its spitting and wont accelarte fast. so my engine service light came on. computer said it was cylinder #4. so shit i just replaced all 6 plugs and all 6 wires. still did it. so i replaced the fuel filter. still does it. i have put fuel injector cleaner in it and gas cleaner and it still does it. and now my clutch went out yesterday so i am p/o, does anyone know what it might be cause i dunno.

ok i have a 98 firebird. ive put a v-force muffler on it and i had to replace the catalytic converter.now months later this is what its doing = it started acting like it was spitting when i would accelerate real fast as if it had water in it. well so i put heat in it which absorbs water. well i ran that down to Empty. still does it. i have used premium gas every since. I can like accelerate at a pace and it wont do it but if i hit the gas to hard then it will act like its spitting and wont accelarte fast. so my engine service light came on. computer said it was cylinder #4. so shit i just replaced all 6 plugs and all 6 wires. still did it. so i replaced the fuel filter. still does it. i have put fuel injector cleaner in it and gas cleaner and it still does it. and now my clutch went out yesterday so i am p/o, does anyone know what it might be cause i dunno.
I had a similar problem with my 99.. 3800 v6... changed wires and all, turned out that one of the coil packs was bad... even tho it tested within spec at autozone. Try replacing the coil that belongs to the #4 cylinder .. I think that one has 4 and 1 on it... not positive as mine are no longer labeled... anyhow.. will cost about $35 and is easy to change.
Andy