I have read the 96+ Fuel Diagnostics thread after having some starting issues when the truck reached operating temps. In the morning it starts right up no problems. After driving for a bit and reaching operating temp it takes a bit to start after you shut it off. I tested to see how long it had to sit for it to start normally and after 6 hours it still hesitated to start. After 8-9 hours it would start right away or with a little chug. The truck runs fine after its starts. Idles fine and everything.

I went ahead and replaced the fuel filter, ICM, cap, rotor, plugs, wires, coil and FP relay, with no fix.

I then tested the fuel pressure and heres the problem. At ON position Im getting 51psi. Its low. but heres the thing, once you hear the fuel pump stop the pressure will drop down to 5psi in a matter of seconds. Turn the ignition off and the same thing. It will not hold. With the engine running It stays between 51-55psi. I have little to no smoke at start-up and no real smell of fuel or line leaks. So you would think if an injector was leaking that much fuel, it would be noticable.

Next thing I need to do is test it from the fuel filter and see if the fuel pump is loosing pressure.

In the mean time anyone have any input? Suggestions?

 

You have a leak. If it isn't external, it will either be the FPR or the check valve in the tank. The pressure test at the filter will let you know.

 

Gotta be the FPR the pump is good because it seems like it sends enough fuel in the am to get it to fire..Then when it gets hot it takes a little to start because the leak is basically flooding the engine in small amounts. I just changed mine and it runs like the ol day's..if you don't change it too much raw fuel well start to mess with your CAT