My 96 f150 dual tanks, one with new pump over year ago, is slow to get fuel up to start engine when been sitting for more than a day. can here fuel pump cycle in either tank, or do I hear a different pump? once started runns fine, starts fine unless i leave it for over a day. It got cold here so battery drains faster but whe warmer it may take 5 minutes of letting pump cyce, turn off ignition and cycle again. THIS IS GETTING OLD. Closest Ford dealer that Id go to to is 35-40 miles. forgot to ask top retired Ford mechanic saturday night. RANDAL

 

It's not the pupm(s). You either have a leaking injector or a bad fuel pressure regulator.

Do you have a fuel pressure test gage to plug into the Schrader valve? Plug it in Turn the ignition to "on" but don't start the truck. See what the gage reads; it should be approx 55 PSI. Turn the ignition off, wait 30 sec and read the gage. It should have lost less than 5 PSI. This will confirm if you have a problem.

Pull the vacuum hose off the regulator. Is there fuel present in the hose? If so the diaphragm is shot. Replace the regulator.

If the regulator is OK, pull your plugs, one at a time. One of them should show rich. The injector in that cylinder is leaking.

 

Thank tou. today it started right up with a battery charger. Now my 88 is acting up. 5.0 5 speed 4wd. Run about 2-3 minutes idling put power to it and it dies. Replaced fuel reg in june. Thanks Agin. Randal