engine missing at low idle and take off. on 1996 Chevrolet S10

Diagnosis says fuel tank pressure sensor, purge valve solenoid, mass air flow, loose vacuum could be the problem. I have changed and checked all of these plus two other sensors and no change in the problem. Please help me! What else could it be?

1 answer
I have seen where cleaning a dirty throttle bore has fixed this. The coking buildup causes turbulence to the air flow and causes stunble when accel and slight rough idle.