What could it be?
 

Hey fellas i got this 1987 gtu non-turbo i've been messing with for a while now. Changed most of my vaccum hoses, replaced plugs 3x, replaced fuel pump, replaced fuel filter, replaced intake man. gasket, messed with the timing, messed with the afm, made sure everything was going good. Yet ill be driving for about 15 to 20 minutes and then my car starts to act up. In the middle of my driving, its acceleration starts to hesitate or not work at all. I'll push into the gas and no response, whether it be not enough gas or too much gas, i don't know. It makes no sense to me, it works fine for 15 minutes and then starts to act up and eventually just sits in the middle of the street rollin or just completely dies on me. I really need some help i'm tired of backing up traffic tired of having to go 2 mph on a 45 mph zone with my 4 ways on. I don't want to let go of my 7 help me fix this problem.

Remove the plug from the TPS and try again. A stuck plunger/wiper on a tps will cut fuel.

what do you mean? unplug the entire thing?

how do i remove it?

Find the wires on the TPS. Follow the wires about four inches from the TPS and you will find a CONNECTOR. Disconnect the connector from the TPS wires.

I don't know how else to put it. Disconnect the TPS and see if that changes the problem.

its the black box on the tb with wires connected to it.