jarnold1213

I've got a 99 F150 with the 4.6. Came back from vacation and it wouldn't start. Everything pointed to the fuel pump so I replaced it and still the same thing. Finally noticed when I cycled the key, the theft would flash and continue to do so. The chip in the key had broke or stopped working. It was the only key I had so I had to have a locksmith come out with his little computer to hook up and completely reprogram and cut a new key. $300 and 15 min later, truck started with no problem.
I attempted to take the truck later that day to get inspected and got almost to the shop and all the gauges fell out and it died. They jumped it, pulled it into the shop where it died again. Jumped it and managed to get it home to park it. I replaced the alternator but the battery light still came on and it won't stay running. Checked the new alternator and the one that was on it and they are both good so I put the old one back on and hooked up a new battery. Same thing. It'll start and stay running if I've got jumper cables on it otherwise it just dies. Not sure what it could be at this point. Any help would be appreciated.

jprevat

iTrader: (1)

I would start checking all of my connections. Start at the battery and work your way from there. When you truck dies is the battery dead? What voltage reading are you getting from the alternator to the battery?

jarnold1213

Battery is new, but is dead. I jump it and it started but idles really rough and as soon as I pull the cable it dies and the battery is completely dead.

jprevat

iTrader: (1)

You have a bad hookup somewhere. I would get a new battery/alternator wiring harness from Tasco or a parts yard. If the alternator tested good and you aren't getting at least 13 5 volts on a multimeter on the battery it's bad wires or connections.