Hi all. I have a 02 f150 5.4 ext.cab. I started having this problem where the gauges would sweep when i turn the key. This turned into now when you get the engine hot you have to let the truck sit for up to an hour before it will start. You can tell when its not going to start because the gauges wont do anything. It will start for a couple seconds then stall and just crank like its getting no fuel. Iv replaced the crank sensor and today the igniton switch because i figured out that if you turn the key on then off enough times the gauges will work then it will start. Neither the ignition switch or crank sensor helped at all. Also no codes and truck runs fine going down the road

any help would be appriciated thank!

 

Moved to more proper forum.

 

Usually, when the gauges start that, it is a sign the battery is going out. I would start by checking the cable connections.

 

could be battery connection, firewall relay, starter connection or the main wire on the alternate has come loose. Less likely but possible is a cable is damaged corroded burned through..

 

Thanks for the advice. I checked and cleaned all my wires alternater,starter and batter cables, even tried putting a diffrent battery in but nothing helped, still did the gauge sweepand not starting issue? The guy at my parts store said it sounded like a computor problem to him, what do you guys think about that? I was just wondering if anyone else has ever seen a problem like this before i have to spend the big money on diagnostics. Im afraid im guna be stranded he soon because its just getting worse.
p.s. What and where exactly is the firewall relay you mentioned jethat?

thanks agian for the help

 

Its next to the battery under the plastic deal that pops open. follow the positive connection to it. It most likely is not the computer. Its a connection you just have to find it.. could be the relay itself is shot..

 

Thanks for the advice jethat. I picked up a complete wiring diagram of the truck today at the parts store so ill be working on it during the day before work this week and let you know what I figue out.