In the last week the truck has done it a couple of times....acts like it is running out of fuel - sorta like newer gasoline trucks with a bad IAC. Once at a warm startup and another time while driving in the city. I'm thinking the fuel pump may be bad. The fuel filter only has about 3000 miles on it at the most and the injection pump and injectors were replaced about 8000 miles ago. Any help is appreciated.

 

Do a pump test then........

Do pressure and flow test on the fuel pump at the Schrader valve on the filter (FSS- fuel shutoff solenoid disconnected). Remove the tire valve core and hook a hose and pressure guage on it should see 4-6 psi when cranking. Then do a fuel quantity test same place, should see 1/3 pint in 10 seconds of engine cranking, route fuel to a suitable container with a hose.

If there is a problem with the lift pump and you are changing it, ensure the new pump comes with instructions as to correct installation proceedure if it is the newer model pump with the almost straight arm.

 

If you do replace it I would block off the factory FP hole with a "chevy big block block-off plate" From autozone. Then I would put an electric FP at the tank, as fuel pumps are better at pushing than pulling... I can look up hte part number if you want me to. Its an in-line fuel pump made by master and is easy to install. It cost me about $45.

This also enables you (if you wire it right) to run it with the truck off after you replace a fuel filter to fill it up w/out cranking...

 

Well, I tested it as best I could. It pumps about a full pint in 10 seconds. This is with the engine running though. As far as fuel pressure at that point, the only pressure guage I have starts at 10 psi so it didn't move at all while cranking. Since the fuel is pouring out at a good rate though I think it just may have been a random particle getting stuck in the line somewhere. I filled up the other day and added fuel additive for the first time in six months and it hasn't stalled since.