1990 Chevy Cheyenne Dies out when you gas it

I have a 1990 1/2 ton Chevy p/u 305 engine. It is a throttle body injected truck. I took it to a mechanic to get it threw emissions, it passed. Now on the way home it started to bog out on the freeway but did not shut off. But now it won't run. it only starts for a second, then when you hit the gas it dies. I checked top dead center on 1 piston. Please give me some in-sight!

I have put a fuel pump in the gas tank a year ago.

I have replaced the fuel filter.

spark plugs gap is correct .035

I put a cap & rotor.

I put on a throttle body sensor.