Ok I have a 93 z28 had it about a year . I dont drive the car that much it has 91k miles , auto, upgrades are simple. SLP loudmouth catback exhaust and K&n ciold air intake...and here is a list of parts that have been put on in the last 2 weeks.. Opti spark , plugs, wires , fuel pressure reg, fuel pump, map sensor, throttle pos sensor, starter,battery,and water pump.. Ok the car runs great after you get past 2,200 rpm before that it has a hesitation on acceleration.. Like it's not getting fuel..it was doing this before I done the tunup . so now I have it at a local mechanic shop..he's the one who put the fuel pump and tps sensor on..it's still not right and everyone is just guessing.. Even the dealership wanted to throw parts at it ..it did throw a tps code but I never saw the check engine light on he said it was in the memory..ok guys any help would be greatly appreciated this car is driving me insane..also have changed all ground wires and the positive wire to starter...

 

You might want to try and run an ECM data log, using the DataMaster software available from TTS Power Systems:

TTS Power Systems

Download, and 20 uses are free. After that, there is a licensing fee. You will need a cable.