My 88 1/2 ton w/350 engine starts and dies doesn't start well either. If you pump the gas pedal it will stay running.If you hold it down it will die and it doesn't idle.When it's running and I pump the throttle it runs a second then starts to die till I pump it again.Like it only runs from an accelerator pump spray.I've changed the fuel pump new, the coil new, tps new,spark plugs new, replaced with good used ign. module, throttle body, map sensor, spark control module. One day I was poking around with it and I wiggled the tps connecter and tried it again and it started and ran perfect I drove it and aired the tires and I started it again and it went to crap again and now runs the same even with a new tps pig tail. ????

The stuff you say that is new, is all of this stuff you put in after the problem?

Yes it started this same thing then took a spell and ran good then would not start. It wasn't spraying any gas out injectors so I put the fuel pump in. It still didn't spray so I put the throttle body on and it tries to run again. And then I added the other parts. None of them made any difference.

Yes it started this same thing then took a spell and ran good then would not start. It wasn't spraying any gas out injectors so I put the fuel pump in. It still didn't spray so I put the throttle body on and it tries to run again. And then I added the other parts. None of them made any difference.

Proper testing before throwing psrtd at it.
Check and make sure you have proper fuel pressure.

Are you losing spark to plugs when it does it?

Any codes or check engine lights?

If wiggling wires on TPS sensor made a diffrence I would check that area for good TPS sensor and wiring and plugin.