The ignition module that is in the distributor is probley bad.
Could be spark in the motor, or the distributor and rotor need to be replaced.
I would replace the ignition module in the distributor.
Bad coil Bad rotor
Things to check: Distributor cap, Plug wires, spark plugs, Ignition coil. On that year this is the most common things that would cause an engine missfire.
Bad coil? Bad distributor cap? Bad distributor rotor?
The 92 model did not have a crank sensor on it. Sounds like it won't start. I would check the ignition module that is bolted to the Distributor plate underneith the distributor cap. That can cause a no spark and no fuel.
A faulty crank sensor would cause no spark and no fuel.
A very good possibility is the opti spark distributor.If this distributor gets slightly damp,it can cause several problems.
Sorry forget to mention it in the motor.
failed relay
The only time I've seen cracked spark plugs was putting them in or taking them out with the socket not perfectly straight.
The bed size is 6.5' of a dimension of 78x9x5 would fit a Chevy 1990 pickup.