Already checked and not tripped (NEXT IDEA) and the inertia switch is on the drivers side next to clutch arm on the 89 f150.

 

Yes, each injector has a filter, and no, that's not likely the cause of a no-start. It would cause an intermittent miss on the particular cylinders whose injectors are clogged.



There are only 2 bolts holding the fuel rail down inside the intake cage. Try to get them out, rinse the injectors clean with carb cleaner (esp. their bottom ends), pry ALL the injectors up gently (leave them in the rail) and see if they all spray during cranking. Apply some clean motor oil to their O-rings to get them to go back into the intake.

Test voltage coming out of the inertia switch while the FP relay is ON. They CAN fail internally.