can the security be removed or bipassed, without spending more than its worth?

this truck starts then dies after 2 seconds, every time. ive tried reseting it several
diffrent ways, replaced ignition switch with no probs, but it would do this start and die
thing often for years,but would reset and start eventually, its been a year now replaced
fuel pump, and filter. examined wires, and repaired some, under steeringcolum,
security light always flashing. i believe it has something to do with GM security
features. several people have looked at this truck lots of money spent, running out of
patience please help.