87 TPI with hesitation on accel.

[scooter0803]

I have an 87 gta with the 350 TPI (8) motor. On any accel it hesitates and misses. we have performed a complete tune up, flushed the injectors, changed out the tps sensor, checked fuel pressure and injector
balance test. replaced the maf. None of this has fixed the vehicle does any ont have any clues? Thanks.

scooter0803

[CKJ]

What all was done in the tune up? Fuel filter? Cap & rotor ( I know...TPI stuff not LT1) Coil?

[96lt1m6]

check the MAF and or the maf burn off relay:thumbsup:

[scooter0803]

plugs, wires, cap rotor, fuel filter. They also replaced the stepper motor
yesterday as well. I'm not directly working on this vehicle another guy in the shop is and I'm trying to help him out, but I haven't messed with the tpi that much. If you raise the rpm slow to moderate it's ok. This only happens when you step on it, and sometimes it works fine but about 90% of the time it stumbbles.

scooter0803

[96slow6]

How do the vacuum lines look? If you have a bunch of little leaks it can cause it to hesitate then pick-up. Is it actually missing or is it stumbling?

[Red Devil]

Test the TPS for smooth graduation. I'll bet you get jumpy readings instead. If so replace TPS.