How can I tell if the Fuel pump (FDM)is going bad on My 95 f-350 460 gas with 2 tanks

Symptom is after driving for 20 30 minutes on front tank engine starts acting like it is starved for gas in an intermittent way. Sometimes it becomes so bad I need to change to rear tank and the problem goes away. Other times it just hiccups for a little bit off and on and then drives ok.

Thanks for any help

Andy

 

Sounds simple but have you replaced your fuel filter? Always start with the small stuff first.

 

Replaced Fuel filter and that seemed to make it a little better. Checked fuel pressure and it seems to drop when engine sputters.

I have only been able to get it to act up when driving and not when setting still. Maybe that is just a coincidence.

 

It sounds like you have a gremlin but I would go with the fuel pump. I had a similar situation with a later model chevy it would always run fine at idle but going down the road it would act up or at stop lights with foot on brake and in drive. 10psi can make all the difference sometimes on these newer fuel injected engines. Could also be fuel strainer on the pump but if you take it all out you might as well replace the whole assembly. imo