back fires and sounds like a gun?
 

Aight i have an 88 t2 large streetport, walbro 255 three inch intake and exhaust, emmisions removed, no secondary butter flys, comp is 115 front and back. And my problem is when its under load and i hit about 4500 to 5000 in the rpms it cuts out an and back fires and aounds like a freakin gun my afm is reading .281 ohms resistance and the tps is .983 ohms at close and really bounch all the way open anyone have any ideas.

what injectors are you running? stock ecu?

Stock injectors and ecu

fuel cut???

^^ this.

do you have an FCD?

Street port + Intake + exhaust = much higher than stock boost. If you don't have an fcd that is most likely your problem.

I dont have a fcd and no boost controler

I forgot to add as well when it does it, it spikes up and then it holds at 5psi and it wont move from there