My truck cranks up and runs good for 2 seconds and falls dead like you cut the key off.... No codes... I'm thinking the AFM is the culprit.. Without spending that money , Is there a way to trick the ECU into thinking it is getting the signal from the AFM?

 

Will jumping the b+ and FP bypass the signal that AFM sends?

 

Yes. Jumping between B+ and FP should keep the pump running.
The FP terminal is the output from the COR to the fuel pump.
That means that you can hook a voltmeter to the FP terminal and measure the voltage while cranking and after the engine starts. If the voltage drops when the engine dies, either the COR or the AFM are not operating properly (or the wiring between).

Don't just assume that because it dies after 2 seconds or so that the AFM is the problem. The COR has two windings that turn it on- one conected through the ignition switch and the other grounded by AFM. The windings that are energized by the AFM may be bad.