BigRooster

OK! First off I have a 1991 Ford F150 300 sraight 6. Two days ago I was going to take my girlfriend out. I went to pick her up, the truck ran fine on the way to her house.. We jumped in the truck, it cranked fine, then we were going down her driveway and the truck just stalls like someone turned the key off, and would not start back. It would start, run for about 2-3 seconds then die, and has been doing this ever since. Well we replaced the fuel filter, and still doing the same thing. Looked at the relays, they seemed fine. It also backfires when you mash the gas to try to keep it running, and it seems like its not getting enough fuel, but it WILL start fine without any troubles at all. It has 2 tanks so I know it's not the fuel pump because I tried both tanks and I know for a fact both fuel pumps aren't out. When you turn the key on you can hear the fuel pump cut on, so we know it's not completely dead. But I'm stumped, and I would like it fixed before my birthday, which is a week from today. Please help me, I know this was long but to anyone who read it thank you so much.

dr_bowtie

say hello to Mr. New fuel pump....

fordtrucknut

yep sounds like a fuel pump. lol

cycle the key on and off about 10 times ( but dont start the truck) then start the truck and see if it runs longer.

and everyone with a 92+ truck should invest in a fuel pressure gauge kit from the parts store and keep it in the truck lol

BigRooster

But how can two fuel pumps go out in the same day? It's got 2 tanks... 2 fuel pumps...

thwalley

You have a low pressure fuel pump in each tank which supplies fuel to the main fuel pump for the injectors. The pumps in the tanks have strainers which could possibly be plugged up with gunk. You will have to drop the fuel tanks to veriFy if these are clean. If the problem is not here it will probably be the main pump.

fordtrucknut

they just do lol

you prolly use one tank more than the other so it sits longer

fordtrucknut

whoops your right, i thought his truck said 92 but it is a 91 sorry.

yeah you have 2 low pressure pumps in the tanks and a high on the frame rail.

sorry for the bad info.

BigRooster

But how is that possible when I have 2 tanks? The last time I used the back tank was about a month ago, what are the odds of them both being clogged up? I think it's something else to be honest with you, like a sensor or something...

mustangGT90210

High pressure pump on the frame rail coulda crapped out

Nitehawkjr

A 91 should only have the two HP pumps in the tanks not the three pump setup. You definitely need to run a fuel pressure check on it to check the pumps, injectors and regulator.

But the first thing i would do is pull the codes on it to see if that would give you an idea where to start.