Fuel Pressure

[RED1985]

OK guys I need a little help. I installed a fuel pressure gauge a month ago and I notice that whne it start up, even after it warm the fuel pressure is right at 5psi. After the run for 15 minutes or more the fuel pressure starts to drop very slowly. It drops all the way down to 2psi after 30-45 minutes. If I rev the engine the fuel pressure never reach back to 3psi, it might only increase .5 psi at most.

New fuel pump and all rubber fuel line replaced. I checked the length of the whole truck for any leaks and nothing.

Any help would be greatly appreciate.


1985 C10 350/700R4