Hi guys, I need some help please. I'm restoring a 92 Z28, the engine hesitates when I rev it, it's gotten better but I can't figure out what it is. Here is what i have and have not done to the car:

• Replaced all wires and spark plugs
• Dist cap and rotor/Ignition Module
• Replaced all cooling hoses and radiator
• New vacuum hoses
• New injectors/New fuel pump/fuel filter/sending unit
• Replaced TPS sensor

What i haven't done

• I thought it was a clogged cat, I removed the Y-Pipe and the cats seem okay just by looking at them. the car doesn't overheat although temp does fluctuate a little. When I hooked up the exhaust the car struggles to start and breath, so I think it's the cat.
• I heard also it could be the temperature sensor under the throttle body? Is there anything else that could be causing this?

 

Could be the temp sensor. Those are cheeeeeep and eeeeeeeezy to swap, and they DO go bad, so ...

Buttt,,, .. sounds kinda fuelish to me. What's the fuel pressure WHILE IT'S IN THE ACT OF SCREWING UP? Not, sitting in your driveway happily idling; but WHILE IT'S IN THE ACT OF SCREWING UP? Tape your FP gauge to the windshield and test-drive it.

 

Thanks, I'll check the temp sensor, have not replaced that. The car sat for a long time (last tag on the windshield says 2007). So I've replaced many parts. As far as the fuel pressure, I tested it from the intake rail while idling, it read 45-50 psi, so that's good, I haven't driven it though.