Started about 3 weeks ago. Thought at first it was bad gas as I filled it up at a different place than usual. Turned over but wouldn't start. Has fuel. Replaced coil, replaced ignition cam sensor, tested fuel pressure, new plugs new wire, new cap, new rotor, used ECM.....don't know how to test that? After truck sits for awhile it starts. Sometimes turns over for awhile, backfires then starts. Took resistor off it starts Put resistor back on it wouldn't start. Seems to be more so when its damp out. Help!

 

Replaced coil and put resistor on....burned out new coil! No ideas??!