hard start, bad running

[rix444]

95 F-250, 5.7l, auto

Getting harder to keep running. This is a progressively worse problem. Ran just great last summer and keeps getting worse. Now I need starting fluid to start it. Luckily my other truck runs like a champ, or I'd be stuck.

Front fuel tank pump has quit. Rer pump works, and I have some fuel pressure on the rail, but what pressure should I have? I can put on a guage, but I don't knwo what the reading should be. It's possible that my back pump is weak. I've replaced the filter.

Fuel problems aside, what else would make it run bad? There's no check engine light, so I can't get any codes.

[mikecee48]

Since the staring fluid gets it running, it sure seems like it's a fuel problem for sure. A cold engine needs a rich mixture to start easy too which tells me that it may have an air leak in the intake system that's causing it to run lean. I'd start by checking the air intake ducting for cracks and loose clamps.

The throttle body could have a leaking gasket where it mounts to the intake manifold. After it's running, spray the gasket area with WD40 and listen for a hiss that would indicate it being sucked in. The engine may run slightly erratic too if it sucks in the WD40 fluid indicating a gasket leak.

Of course, a failing fuel pump or fuel pressure regulator could be the culprit too, but it would seem that if either of these were at fault, the engine would starve for fuel and misfire or bog down at higher RPM's or under a load.

I recall the pressure on the rail should be about 35psi, but you should verify that.