2002 Mercury Mountaineer • 125,000 miles

My 2002 Mercury Mountaineer has been have problems starting after it sits for longer than 6 hours. It sometimes cranks and cranks and eventually after 10 minutes, it will suddenly start as if nothing was wrong and runs fantastic all day long. But once again, if it's left for longer than 6 hours, the battle to start it again begins. I've been told it's the fuel pump, but my car has never stalled out, runs fine all day long. Injectors are fine. But yesterday a friend who knows cars said was my "theft" light flashing as soon as I put my key in the ignition? YES, I had noticed lately it never did that before. He said my anti-theft system that is stock on ford's, needed to be recalibrated and the anti-theft was kicking in and not allowing the car to start. IS THIS TRUE? Can it be somthing so simple? How do I fix that?
December 2, 2012.
