I had to replace the battery in my 2002 F-150 Lariat and it ran fine to and from work for a day and a half. On the second day I got ready to leave started the truck put it in reverse and backed up about 15 feet and it shut off. After that all it would do is turn over. it was obvious from the sound that it wasn't getting fuel and thats when I noticed the theft light flashing rapidly. I've gone thru and checked all the fuses both inside and under the hood. I had a locksmith come out to make a new key and reset the PCM to no avail. Today I replaced the 30A relay's for the fuel pump and PCM. It was suggested by the ford dealership that its either the key or the ignition immobilizer transceiver. I really don't want to play the replace parts til you get the right one game or take it to the dealership and have them give me a proper raping. Does anyone have any ideas what I can do? short of dousing it in kerosene and setting it ablaze, which I'm getting closer to doing every second.

 

The battery replacement timing was coincidental.

Look at the odometer display. Does it look normal or not?

Can you get into the HEC Dealer Test Mode (Google it)? Any stored DTCs?

Was the locksmith able to communicate with the PCM properly when he tried to program it?

 

The same happened to me last week. Replace the 5A relay for the anti-theft. The owner's manual will show which it is.

 

There's no such thing as a "5A relay for the anti-theft".