Won't start or starts and runs good. Put new cam sensor in didn't help. Put on computer while running, shows OK. Turn off then won't start. Any suggestion??

Thoughts:

. Ensure the oil and filter have been recently changed. Oil should be up to the "FULL Line," since it affects fuel pressure.

. Ensure under hood and under frame fuel filters have been recently changed. Purge system of all water.

. Check fuel pressure. Old, tired fuel pumps are problematic on PSDs, especially after the engine heats up and tolerances increase.