Ford F 150 Lariat 5.4. Problem started with battery, then alternator. After replacing both, still had issues, changed fuel pump. That wasnt it, shop then used code reader, diagnosed as Gem Box, then replaced . Continued to have electrical problems, dealership diagnosed main computer, then replaced. Everything worked fine for two weeks, then it wouldn't crank, with antitheft light on. Replaced ignition switch, it worked for a day, then stopped cranking. Replaced fuel filter, then it cranked. Then again, theft light flashing, and no crank. So I reset ignition switch by leaving key in "on "position for 13 minutes. That did it, But now, if I leave the truck off for more than an hour (Ive tested it), I have to reset the ignition. This is factory installed, and I dont see a way to disarm the system without actually activating it. Any ideas on how to solve this?

 

What year?

 

2001 Lariat, 5.4

 

Have you replaced the fuel pump relay with a different one ?

I had the same thing on my 2001 ( back in 2005 ) and it was a bad fuel pump relay and would have the same intermittent crank no start.

https://www.f150online.com/forums/v8...e-my-cure.html

The other item of note, make sure you do not have another transceiver by the key when starting ( Mobile Speed Pass, another PATS key, etc ) as this can cause the crank no start issue also.
- There was a TSB on this back in the day.

If you get a crank no start; turn the key off turn back to the run position ( not start ) and wait for the cluster self test to finish. If the theft light goes out it is not an issue with the PATS system causing the crank no start.

Not too sure who gave you the "reset ignition switch" line, but that is nothing on a 2001 F150.

The PATS receiver is around the ign switch and the PATS key(s) are stored in memory in the HEC in the instrument panel.
Leaving the key on for an amount of time will not store a PATS key code, there is a process to program them if you have 2 keys and if you have one you need a Hicks unit or NGS to erase and reprogram new keys in the HEC.

 

Well Im going on a week now of crank no start after sitting for more than an hour, and being able to crank after letting it sit in the on position for "8-13"minutes. I got that from the ignition packaging, and so far thats how Ive been starting the truck each morning. So Im not sure what all else you are talking about. I can hear the fuel pump engaging, checked the spot up front too to make sure it was coming through.