i have a 2003 super crew with the powerless 4.6. here's my problem. the truck will start and run fine for a day or 2 and you go out and try to start it and nothing, wait a while and then it will start, next day or so it will do it again like clock work. the odd thing is when it won't start the doors lock...so far i put an ignition switch in and a starter. battery has 12 volts. i think it's in the anti-theft system..any thoughts?

 

That sounds like the passlock system going crazy on you

 

I had a similar problem last week and it turned out that my terminals on the batt were loose.. replaced them and havent had a problem since

 

i want to say this happened years ago and we replaced the battery but can't remember

 

The battery should have above 12 volts. Typically, 12volts and under is considered a dead battery. A good battery should read 12.6-12.8 volts. (2.1v per cell). With the alt running the truck should read from around 14.3-14.4 depending on your wiring and electrical appliances. A battery that reads 12V and under may not have enough power to turn over your starter. It seems like a small difference, but that voltage is imperative to the amperage to turn over your starter.

 

I had the same thing happen to my 2001 5.4 and it was the starter solenoid. If it happens again, turn the key on and use like a jumper cables and connect the two terminals on the solenoid and it should start if thats the problem. Its on the passenger firewall

 

Last year I had the same trouble, I thought it was the anti-theft or whatever it is but it turned out to be the starter solinoid

 

I had the same problem. It was my security system. I didn't even know I had one. So basically, if you sit in the truck and lock the doors with the key fog, then unlock the doors with the key fog and open the door and then close the door and do not lock the doors it should start if your security system is the problem.

 

97-150..thanks man this worked but we are now having to do it often