89 ford f150 v8 firing order and timing marks how do you check to see if piston 1 is firing?

To check if piston 1 is firing, you can remove the spark plug wire from cylinder 1 and hold the wire near a spark plug while the engine is running. If there is a spark, then the piston is firing.

You can also verify this by removing the valve cover from the cylinder head and checking to see if the valves for cylinder 1 are opening and closing properly.