dombonfire1

'96 4X4 xlt (auto locking hubs)
5.0 liter

Symptoms:
Truck turns over, but doesn't fire up.
Doesn't happen all the time (intermittent and random).

Details:
Truck always turns over, but doesn't start, here's what happens when it doesn't play nice... I put key in ignition, and turn to "run" position (position of key when driving. i know you know). I wait, and listen carefully. After a few minutes (from 2 min to 40 min), I hear a quick buzz sound. Then, truck fires up. Again, this happens sporadically... i'll go a month with no problem, then it misbehaves. (edit) Also, the problem occurs no matter which fuel tank I have switched on.

Also, it shuts off in the middle of driving every now and then. I know this is related, because when it does, and i pull over, i have to wait to restart it as described above.

Things i've tried:
Replaced fuel pump relay (two seperate tanks)
Replaced EEC relay
Replace ignition switch

Any ideas/help is greatly appreciated!

1990BlackF150

im not going to lie, im pretty sure this pertains to the fuel pump, have you replaced that? i seen you replaced the fuel pump relays, but how about them pumps? have you tried both of the tanks when trying to start it? you might have only one bad pump. ive had the same symptoms as you in my dads truck, and we did mostly what you did, but then dropped the tanks and replaced both pumps. i hope this helps and doesnt tell you anything that you already know.

dombonfire1

Thanks for the comment. No, I have not replaced the fuel pumps. I haven't tried that yet because I know I have two seperate tanks, two seperate pumps. The problem happens no matter which pump I have switched on (forgot to mention that). However, it's still an option for me because, who knows, maybe both pumps are going at the same time. Also, I misspoke earler. I replaced the single fuel relay (one relay for both pumps)

It was suggested in another forum that it might be my fuel filter. That's a cheap thing to try, and will do that today.