5.4L won't start every once in a while

REDSWAY

MEMBER
FORD F-250

1999 Ford F250 5.4L Auto

Truck won't start every once in a while. At first I would spray starting fluid in the airbox and it would fire right up. Then not even that would work. I changed the fuel pump and filter, ran fine for a couple days, then it did it again. (Both times the fuel pump would run and run). Then I changed the relay out and it ran fine for another couple of days. It ened with the same result of the fuel pump running and not ever stoping (only when key is on though (same as always)). So I unhooked the battery for a couple of minutes and now the fuel pump doesn't even turn on! Still no start. I was told that it could be an oil pressure switch or the computer (cause it controls priming). Anyone agree with one of these or have a better idea?

Now it sat for a day and it is starting like a new one again. But it will not start again within a week or so.

1 Reply

LAX89

MEMBER
2 POSTS

I drive mustangs, but what is true in some cases may not work in yours. When cars get older the computers, I guess homeostasis, goes out of whack. In mustangs all you do is turrn of EVERYTHING (heat/ac, radio, headlights, etc) Disconect the negative battery cable for about two minutes, then reconnect it. Fire it up (if you can get it started) let it run with ALL of the accessories ON for about 5 mins. Turn everything off again, shut the car off. Then wait 2 mins and restart it. Like I said this resets the Mustangs computer, I don't know if it will help you but its worth a shot