Chevrolet Repair: 350 motor trouble, throttle position sensor, fuel pressure regulator

Question
I have a 1989 350 tbi motor. the motor idles good but runs really rough when the throttle is pushed. I have replaced the fuel pump,filter,accelorator pump, and tpi but no effect.

Answer
There is no accelerator pump on a throttle body.
I don't know what you replaced called a TPI.
There is a throttle position sensor that could cause it to act like that.
Low fuel pressure would also, and unless you test it with a guage, and get 13 PSI while running, you can't tell if the fuel pressure regulator is working correctly.

A EGR valve opening, or a vacuum leak could cause it also.

Another thing to check it the MAP sensor, which measures manifold vacuum.

Van