This truck had intermittent throttle problems, so I changed the TPS & it fixed that. Now, usually in the heat of the day, it will shift to second gear & when it hits about 3000rpm it boggs out till it hits about 2000rpm & picks back up. I change fuel pump & filter. What else could it be?

 

Do you have a fuel pressure gauge?

 

I do not have a fuel pressure gauge. I changed the transfer pump & still no difference. It still intermittently cuts out.

 

More than likely if your transfer pump was bad for very long your injection pump beat itself to death trying to do all the work. You need gauges to check the in&out fuel pressure on the injection pump.