Hey guys I am a new member I really hope someone could help me out I have a 2002 f150 with the 4.2 v6 got about a hundred and sixty thousand miles on it all original and the problem I'm having it's starting to misfire I change the spark plugs and wires about a year ago the crazy thing about this issue it doesn't do it all the time it started misfiring really bad this morning to the point it was backfiring and the check engine light was blinking off and on I do pray that somebody could help me with this issue thank you.
Chuck

 

Check for DTC first. You don't need CEL illumination to have a code stored in the KAM with these trucks. A blinking CEL produces DTC's as well.

 

Yep. There are a lot of possibilities to the cause of a misfire. Best to start with seeing if a code is telling you what the problem is instead of chasing it.

 

If it's just blinking (misfiring), at times you may have to repeat within the same drive cycle two to three times. So hold engine load at misfire point as long as you can. That way the misfire monitor will bring the count up and store DTC. The monitor requires a high count.

But still, you do not need solid CEL illumination to have produced a DTC in KAM (KeepAliveMemory).

 

You were the one that taught me to hold it at the point where it switches to overdrive in order to force the misfire. That worked well for me.

 

Yea, works great for bringing the MF count up lol.