First off, the anti theft system (if we are talking about the PATS Passive AntiTheft System) in that vehicle cannot be bypassed. It is part of the PowerTrain Control Module and PATS module and cannot be unprogrammed or removed without making the vehicle inoperable.
But with your concern, lets take a look at a couple of things.
One, the PATS disables the ignition circuit, therefore, if the PATS was a problem, it would not run on starting fluid.
The inertia switch is on the power side of the circuit, however it will only have power for a few seconds (about 5) when the key is cycled on. This is normally a 2 person test, one to check for power to and through the inertia switch and one to handle the ignition switch.
If you do not have power to the inertia switch, then you probably have a bad relay. However, it will not stop there. The main reason that the relay fails is due to excessive current flow and arcing of the relay contacts. This is normally caused by a failing Fuel Pump.
But, having said all that, chances are you will find that you are getting power to the inertia switch and the fuel pump is just plain not working. This is pretty common on vehicles that are over 8 years of age.
I HAVE ALL READY CHANGED THE FUEL PUMP AND FUEL PUMP RELAY WILL THE MASS AIR FLOW CAUSE NO PULSE AND WHERE IS THE VIP CONNECTOR TO CHECK FUEL PUMP POWER AND IF I CHANGE THE COMPUTOR WILL IT HAVE TO BE FLASHED
No, the MAF can be completely unplugged and the engine will still run.
On OBD2 (everything built after 1995) vehicles, there is no connector to test jump the fuel pump.
If you replace the PCM, the data will hae to be removed from the old computer and installed into the new one. This can only be done with the proper computers (read Ford Dagnostic Computers).
Did you check for power at the inertia switch the way that I asked? And what are the results?
Okay, that means that the fuel pump is getting power.
Next question: is the theft light flashing fast on the dash when you are trying to start the truck?
Okay, there is the problem. You have either a bad key, an unprogrammed key, only one key is programmed into the system (the PATS needs to have 2 keys programmed in before it will enable the PCM) or a bad transponder.
If the keys are original then I would be leaning on the transponder. This is the sensor ring mounted on the steering column around the ignition lock cylinder. This part has a problem with the wires breaking due to the column tilting.
Tell me about the keys that you have and lets try to isolate the problem.
As long as the keys have not lost their programming (rare) then the transponder can be replaced without having to program the keys again. The transponder is pretty easy to change out as well. You will have to remove the lower dash cover and brace and the steering column shroud, as well as the ignition lock cylinder. The transponder is held in place with a single screw and the wires are clipped in place.
Quick test: tilt the steering column and retest the truck. I have seen this allow the PATS to enable and let the engine run.
You are quite welcome. Glad that I was able to help out a little.
Have a great Thanksgiving.