Ok guys I had trouble with my 95 auto, chuggin or missing at low rpms. It some times starts with no pedal, the next time it may turn over a little an then start but chugs until 1800 or higher rpms and runs good. So I checked all the lines first off an changed the filter an clean the fuel heater screen. Pulled out the ofv an replaced it with another one it seemed to have fixed it. Today its doin it again so I pulled the ofv first off made the spring a little longer. No change! I hooked up a 0 to 100 psi gauge on the injector pump at first the it jumped from 0 to 20psi at 700 rpms give it fuel an it will jump to 25 an wide open 0 to 15psi an then will stay at 0 but not always. The gauge is new off the snapon truck. Is the the lift pump bad or is it a return problem? The truck has new injectors new fuel filter , I do have two injectors that just won't stop leakin return fuel Thanks for any help!

 

With the engine running pinch off the rubber return line with pliers.
If your fuel pressure gauge doesn't shoot right up to 60 psi or more the lift pump is bad.

 

Im gettin ready to go try it thanks for the info!

 

Put the gauge on the truck clamped the return line on the back side of the pump. The gauge went to 60 psi and over,so the lift pump is good so now. Im down to the return valve any other tips would be great thanks lots.

 

Only things that can cause low fuel pressure besides a bad lift pump are the OF valve or restriction in the supply.
Could be plugged main, pre or tank filter or a kinked line.

 

I have a ofv coming wedsday, Im getting ready to replace the lines with ruber lines front to back, That what I had to do to my 91 last year. Thanks for the help Bill.

 

Hmmm.... im subscribing to this. I have the same problem. And doing the same things, replace fuel filter, healthy dose of fuel treatment, cleaned the fuel heater screen. DID find junk, n metal shavings though..... Stretched the OFV spring, and ordered a new one, I am waiting on that now. LP seems to be very strong, once the system became primed you couldnt pump it anymore!

Does yours seem to do it more when its warmed up?

 

Made any progress? I got my OFV in the mail thursday and put it in friday morning, made a difference with the truck as a whole, but still having the same issue. Acctually was missing at an idle this morning too. Guess next week is fuel line week. Drats! Have to go n get a big line kit n a draw straw, poor poor me!