why does my engine load up after getting fuel on 2004 Chevrolet Express 2500

also does the same thing when backing in a steep drive way it happens intermittentley i can clear it out by revving the engine

Asked by for the 2004 Chevrolet Express 2500
Most likely the fuel pump pump is going bad. Will need to check pressure and volume. They go bad right around 100k.
I found that to be the EVAP Purge Control Solenoid located at the throttle body. Everytime i filled up with gas van didn't want to start. This fixed it.