Hey everyone. I have a 95 Ford F-150 XL 300 4.9L a few weeks ago I started having problems with it. When I would turn key on engine off I would hear the fuel tank pressure up but keep running. So I switched tanks and it kept doing the same thing. The CEL light would come on so I would switch the key off and on until the tanks stopped running only then would it start. It's a great running truck but then as I'm running down the road sometime the cel light would come on and the power would want to die and it would do that sporadically and then it would stop and the truck would run great again. I've recently had both fuel pumps replaced and replaced spark plugs, plug wires, distributor and rotor cap. So when it runs it does run good. What could be the problem? Please help.

 

Could be a CEL issue. POSSIBLY a sticking relay ? comes to mind. Try a new one maybe. I take it you've pulled the codes first off. The computer will quite often tell you more than anybody on here can.

 

Yes, I replaced the Pcm relay and pulled the codes. The only code was 512. I checked the fuel pump regulator thinking that might be it but it was fine.

 

^^^

 

To eliminate the possibility of a bad computer pull the computer, open it up and look at the board. Leaky capacitors are easy to spot and smell.

 

Check your fuel pump relay for corrosion. They can be corroded and have an intermittent concern like yours.