I had my spark plugs change 6k miles ago and my check engine light came on so I pulled the codes it says that cylinder 6 is misfiring is it the spark plugs again

 

I don't know if this will apply to Ford but awhile back my wife's jeep was throwing codes calling out for a misfire I put on a new throttle position sensor and that took care of the problem

 

Might also want to check the plug wire is seated, just a thought.

 

My 4.2 also had a misfire come on at times. Change the sparkplugs and sparkplug cables. Piston number 4 cable was bad and just did not fire all the way to the sparkplug.

2007 F150 with 100,645 miles and runs like new now.

 

Check the plugs too, I had a similar problem after the dealer changed the plugs and several of them had started to back out...

 

Could be plugs, could also be the boots, or the COPs, or an injector.

Swap the COP, if the symptom moves or goes away you've found the issue.

 

Or they could have miss gaped that plug (#6)

 

IIRC, there's no gap adjustment on the plugs for the 5.4

 

Ok, I learned something new. Thanks

 

What kind of plugs did you have installed ???