I have a 1992 F150 with a 300/6. I was using it yesterday, and it quit running. When I tried to start it, it would crank, but would not start. I sprayed a little starting fluid in the air intake to see if it was a fuel issue, but it still wouldn't start. THEN,, I noticed a small amount of smoke coming up out of the dash on the drivers side, near the defroster. It has a burnt smell now, and still won't start. Two things come to mind for me,,,,,,,,,,, COMPUTER, and the IGNITION SWITCH.

Any ideas??

 

Does the vehicle crank? Have you checked fuel, spark, and all interior/exterior fuses? Test for the obvious first and see if that narrows down things by process of elimination.

Take a used spark plug laying around (.044" or more) if you have one, pull a wire off a spark plug and put it on the spark plug while grounding out the threads on the intake manifold.

While cranking, do you see a bright thin blue spark?