Need help on problem with 1994 Z28.

[locrian]

i have a 94 z28 m6 with 70k on it. it has an issue. when you are accelerating hard, it will pull strong to about 5k, then it starts missing. it is hard to describe, almost a sputtering, it still pulls, but there is a noticeable drop in acceleration. the more you do this (the more it warms up?), the worse it gets, ie, it will atart doing it at 4.5k, 4k, etc. now, you can rev it up as much as you want, as long as you do it somewhat slowly.

any ideas? i'm thinking fuel pump maybe?

i have already replaced the optispark and plugs and wires.
Edit/Delete Message

[Sarge]

Fuel Filter
Injectors
Valve Springs
Coil
Rent or buy a fuel pressure guage.....hook it up....read your fp from that....should be around 45'ish lbs...I run 62lbs but I got a beast for a pump Eliminate the fuel issue...change the fuel filter....after you have changed the ff and verified fp....and they are good...if it still does it....go after the injectors....I'd have a injector cleaning service done on them first....after that....if all the fuel issues are not the culprit....I'd go after electrical...coils do this....when they get warm...they shit the bed earlier and quicker.....diagnoses is a matter of elimination.....Fuel pump would shit the bed regardless of engine temps ( I'm thinking to myself and typing here )....Slap in a new fuel filter and a new coil....try those first....
It could also be a clogged catalytic convertor....come to think of it....From the symptoms you described it sounds exactly like a clogged convertor.....have a decent muffler shop check it out...

[locrian]

Fuel Filter
Injectors
Valve Springs
Coil
Rent or buy a fuel pressure guage.....hook it up....read your fp from that....should be around 45'ish lbs...I run 62lbs but I got a beast for a pump Eliminate the fuel issue...change the fuel filter....after you have changed the ff and verified fp....and they are good...if it still does it....go after the injectors....I'd have a injector cleaning service done on them first....after that....if all the fuel issues are not the culprit....I'd go after electrical...coils do this....when they get warm...they shit the bed earlier and quicker.....diagnoses is a matter of elimination.....Fuel pump would shit the bed regardless of engine temps ( I'm thinking to myself and typing here )....Slap in a new fuel filter and a new coil....try those first....
It could also be a clogged catalytic convertor....come to think of it....From the symptoms you described it sounds exactly like a clogged convertor.....have a decent muffler shop check it out...

hmmm, i've heard that before. is there any disadvantage to me just removing the cat and welding pipe in there? crappy sound, performance, sensors screwing up?

thanks for the help.

[Sarge]

You'll need some SIMMS I think ( not sure on that year of car)...to fool your ECM or it will throw a SES light....

[BlackLT1Z28]

No, you don't need sims on a 94. You just need a tune to zap the SES light.