Check the power wire that is connected to the + side of the coil,
if power is there when the ignition is on, replace the distributor, I
think you have a bad pickup, OR check the wire from the distributor
to see if it's attached.
Second thought, Does your truck have EFI or is it still the Carb engine?
if it's an EFI model, you might have a problem in the ECU, tho it's the
fuel injector that stops working on the Sidekicks when the caps repture
and eat the circuit traces
Wild