My car has recently started to hesitate horribly when trying to accelerate. It does it the worst between 1-2k rpm's, but also has doesn't have near as much power as it should at higher rpm's. Speed seems to have no bearing on the condition, only rpm's.

This came up very abruptly, and i am very concerned about it. My brother who is an ex-mechanic thought maybe the fuel filter got clogged, and suggested i start by testing the fuel pressure, or just replacing the filter, since i don't know if it has ever been replaced. Is there anything else that could be wrong with it??

The car is a 95 z28 with 72K on the clock. The plugs and wires are only 1000 miles old, so it shouldn't be them. Also, when i start it when it hasn't been driven for awhile, it will start, rev up to about 1500 like normal, then quickly fall to 500 for a second, then come back to idle. The first time it did this i thought it was gona die. Any Help??? Please???

Jeff

 

I had that problem in my firebird i sold it before i got around to fixing it. I changed the opti and it didn't help at all... The car only hesitated when it was warmed up fully. When it was cold it would had no hesitation whatsover

 

Yeah I have that problem as well. I have replaced the plugs/wires, which helped a little, new opti, which didn't affect anything, LT4 knock module, no change. You should replace the fuel filter just in case, but that probably won't be the source of the problem. It could be a clogged cat or maybe a toasted sensor (O2 or coolant temperature)

 

My firebird did that before my cat got clogged then i had it totally gutted when i put my exhaust on and there was no difference.

 

Sounds like you either have a bad TPS or real sticky EGR valve. I would replace the TPS and clean the TB real well. While you're there, remove clean and reseat the IAC. Then remove, clean and test the movement of the EGR valve by sucking on the hose to see if the movement is smooth. Put it back with a new gasket.

It also wouldn't hurt to see what your vacuum level is at the engine.

 

ttt