The being that the code said crank sensor, and the book said injector driver, could it be the optispark?
The notched wheel inside the opti provides crank and cam position data to drive the injector and spark timing.
Maybe some of the wiring to the opti is damaged or you have an intermitent(sp?) short somewhere in the circuit.
Try pulling the plug from the top of the opti... Sometimes it gets corrosion damage and a good cleaning of the contacts works wonders.