1989 f 150- with 5.0 EFI Won't feed continous fuel, down powers, backfires, etc...
Just started going down the road yesterday. Like it was dying out...pumped the gas to keep it moving. It has duel tanks. I switched tanks thinking it might be a problem with the gas, or that tanks internal pump. No change. I have since installed a new relay, fuel filter, and pressure pump (on the rail) and it did the same think this morning. I am really at a loss-its like it is not getting gas. Firing is good. Pressure in the gas line is good at the relief port on top of the engine. Any ideas?
A backfire normally indicates preignition on older vehicles relating to timing. It can be raw gas getting to the Cat Converter on newer vehicles and igniting which could be construed as a backfire. After determining which type of ignition system you have I would check along those lines first.
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