I have a 90 f150 5.0 plenum with what I was told a 5.8 block. Thats what the mechanic said. Ok, front and rear tanks. On the rear tank the engine backfires. It is at the motor and not the exhaust. It doesnt accelerate very good at all. When I switch to the front tank you feel it kick and go. Now on the front tank it doesnt backfire but it does jerk a little. So again, rear tank it backfires under the hood and runs like crap, but once I switch tanks it runs much better but still feel a jerk every so often. On the front tank when I give it gas she accelerates great, but when it is running at a steady speed you feel the sputter. Please help anyone, thank you in advance

 

Sounds like you need a fuel pressure test on all the pumps. And maybe even a new fuel filter.

 

hey jgger, thank you. i put a new pump in the front about 2 months ago as well as a filter. I bought the truck in april and the guy said the back tank pump works but only to get you to a gas station if the front tank runs out. How many pumps are there. I know one in each tank and sounds like more. thanks again

 

I think there are 3, one in each tank and a high pressure one on the frame after the switching valve.

Sounds like the one in the rear tank might be below spec.

 

ok jgger, thank you. i had a pressure test done. rear tank at 25 and front was really good just dont remember. i changed the filter 2 days before the new pump and sending unit in the front tank. i wish the damn engine light would come on and save a lot of aggrevation. i thought about a TP Sensor, but the engine light would come on for that. i like my older trucks, less problems