I have a 1991 TA TPI 305 w/5 speed.

It is modified with:

SLP headers and 3" exhaust
Crane Cam
SLP intake runners
SLP air foil
SLP High Performance chip
Crane roller rockers
TPIS big mouth intake
Accel 23# injectors
AFPR set at 47 psi
Racetronix high flow/pressure fuel pump and wiring harness
New fuel filter
All new ignition items (wires, cap, rotor, etc)
Jacob's Pro Street Ignition

The car is very fast and responsive except at WOT.

At WOT the car jumps and hesitates. Right before WOT everything is fine.

What could be causing this?

I am going to put my stock chip back in to see if the advanced timing is a problem or maybe something else with the chip?

I already put the ignition back to the stock coil and it didn't make a difference so it is not my Jacob's Ignition.

I am really puzzled.

Thanks for any suggestions.

Might have too much timing advance. Try backing off the timing 4-6 degrees, and see how WOT is then.