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Ok, here's the deal. The vehicle is a 95 F-150, single cab, short bed, with twin tanks, and a 5.0. It has been quitting after a load has been put on the engine (it will idle all day) so I figured fuel supply is the problem. So I replaced the filter, now it takes much longer for the truck to stall (It went for three miles on the freeway without dying), but it's still dying. I don't know where to go next at this point, maybe there are crusties in the tank large enough to plug the fuel pick-up? Anyway, clues, ideas, experiences?
Sounds like the fuel pump is not doing its job. Can you verify that the pump is running after the truck stalls (by switching the ignition off and back on). If the pump is stopping for more than a few seconds at a time the engine wouldn't idle long either. So either there is a lot of stuff clogging the line, your pump is defective, or your pressure regulator is defective. A fuel pressure gauge would help pinpoint the problem.
Well I just reread your post and you have two tanks. So I doubt that both fuel pumps would be defective, or that both tanks/lines would have enough trash to clog the lines. So I'm thinking it's your pressure regulator. I assume you have tried switching tanks when it fails.
In 1998 I had to replace both fuel pumps on my 1992 F150 (5.0 L). NO explanation, and it cost nearly $1000. There were some tell-tale signs prior to the big event at 60,000 miles, and overall I was (and still am) quite irate about this problem. I hope it isn't what you have, but it sounds familiar.
The indications were sluggish acceleration, especially on hills, and we had temporary good luck when switching out a fuel filter. However, living with it was not an option, especially when we broke down on Interstate 5 headed into Los Angeles and had trouble returning back home to Monterey. It was a rough trip. Good luck, and don't push it!
I have a '92 F150 4.9L w/M5OD transmission. Both fuel pumps went bad in 1996. The cost was about $800.00. I was pretty upset like the other guy that answered you. I even wrote Ford about the problem but got nothing more than a too bad letter in return. The pumps have been working fine since. I have heard that you should always keep the pumps cool by not running down below 1/4 tank. I have tried to be true to that and have not had anymore problems. The fuel pressure regulator may fix the problem. If that does not work you are probably going to have to drop the tanks and take a look.
How do you get the truck restarted ?...does it fire right back up or do you have to wait a while..keep on trying ? Next time it stalls, pull over without turning the key to the off position,just leave the key in run for now,, and check for spark right way while cranking. If no spark or vey weak spark...fix that problem first. The computer has to see RPM via the ign module in order to keep the fuel pump relay turned on. If spark is good, check fuel pump relay operation next.
Phil
I feel your frustration. I have very similar problems with my '91 302. I have terrible problems with the vehicle hesitating, bucking, and even knocking while going upgrade. It usually only happens when the engine is warm. I have tried everything I can think of with regard to the ignition system or feedback system to try to get this thing to work properly, to no avail but to considerable expense. Both of my fuel pumps are very loud. I get good fuel pressure readings at idle, but now I wonder what they would be during driving. I guess I have to rig up a fuel pressure gage and watch it while driving to see if it is steady. The dealership sure is clueless and I am very frustrated.
It's been fixed, the overflow valve between the tanks was causing the problem. Unforunately I couldn't figure it out so he had to spend money to fix, but it's fixed...