93' W2250 5.9L Magnum

Getting my plow truck ready for winter, been parked since April.
Turned key, nothing, left key on crossed starter terminals
and fired up, ran great.
Backed it into shop, shut if off, again no crank.
Pulled starter, cleaned termials, bench checked OK.
Reinstalled, no crank.
5 pin starter relay wasn't working, cleaned terminals, still nothing.
Had an 4 pin from an 88', plugged it in, it cranked over, wouldn't start, no spark. Put original 5 pin back in, cranks over, no spark

Pulled spark plug, no spark, pulled plug going into coil, no voltage at plug when cranking. Checked all fuses, ok.

Could it be a crank position sensor?

Any other thoughts? Appreciated.