Truck started misfiring last night and check engine light was flashing on and off.I have no diagnostic tool to pull a error code.How do I test to see if a coil is bad?My guess is coil,plugs or plugwires.Truck has 149k miles w/original plugs wires and coils. I don't even know how to get to the plugs to change them,can't see them. TIA ,Mike

 

Might be time to change those plugs and wires. I had a 97 before I boutght my new lightning. I did have a misfire problems twice. Once it was a plug wire with a hole in the boot, right after i chance them. The other time it was a boot dry rotted . The boot was number 7 i think, the third one on the passenger side. My buddy is a tech at a ford place and told me that that wire goes bad cause the rain drains right on it thru the windshield wiper cowls grating. makes sense to me. Hope this helps. Ths plugs and wires you can get at any parts house but i reccomend napa, never had too much luck at autozone. I put accel wires on last time and they were the same price as stock. i bought them at truckperformance.com . Good luck.

 

This may help you, I was fighting a missfire issue for 4 months with no luck at all, try this post I submitted.

https://www.f150online.com/forums/sh...hreadid=171560