01 Sport Trac Anti Theft light

[David-sport trac]

Hey guys need some advice, I have 2 trucks one is fully functional except for the anti theft system. The other runs but needs a bunch of parts to ride on road. So I’ve been trying to get mine to run so I bought a new code reader (black box under key tumblr) didn’t help changed the whole steering column out of other truck and computer swapped and nothing worked, so I swapped computers back out and key tumblr back to mine and it does the same it will crank every few days and run for a few mins then throw theft light and cut off fuel pump I’ve been told to have it flashed and reprogram but I’ve been reading where a lot of people say that most of the time doesn’t help, not being made of money wanted to see if anyone could help me think of any ideas or reassure me on the flashing and reprogramming ordeal.

NOTE: I can take computer, key tumblr, and steering column and still crank parts truck just mine throws theft light. PLEASE HELP