1997 Chevy Astovan, Intermittently when making lest turns the engine will quit. It will restart right away. Also at large angles like going up a steep hill, the engine will appear to run on only 4 cylinders. It will continue to run like this even on level ground. Shutting it off and restarting sometimes clears the problem. When it is running badly, disconnecting the crank sensor the engine runs fine. It has been a real puzzler for my mechanic. Previously the fuel pump had been replaced due to low pressure. Mass air flow sensor has been changed as well as the distributor.
I would say you have loaded up your question with too many qualifying parameters for anyone to give anything but a guess, perhaps not.