I just changed plugs on my 4.0 ranger and it seems the passenger side front plug keeps closing the gap to nothing on this plug, I don't think I stripped the hole the plug threads in nice and I'm using anti seeze, gone through 6 plugs ,what would be causing this?

 

Just tried 2 new plugs and same thing happened, ran fine before I changed the plugs,only running on 5 cycl

 

What kind of plug? Pics?

 

Motocraft

 

It has bent 10 plugs now?????? Motocraft plugs from the ford dealer only doing passenger side front plug

 

Here is a picture

 

I can't believe you bent that many plugs that's strange

 

Can you get an inspection camera into the spark plug hole and see what is happening?

 

Don't have one but will put my magnet in there and see if anything comes out, sure got me stumped, even if I stripped threads this should not happen

 

i experienced the same problem

the coil was not firing that spark plug very often , even the spark was very weak

turns out there was a huge amount of carbon build up in that cylinder , the hard carbon on the piston head was closing the plug gap

take a long shaft screw driver and gently scrape the carbon off of the piston directly under the spark plug hole

you better start using seafoam to clean out the cylinder

some 08 to 10 4.0l cylinder had spark plugs that were not threaded in completely thus causing incomplete combustion in that cylinder

 

Thanks I will check that out, can't see how I have carbon when I mostly highway drive, also use seafoam regularly

 

Well had a mechanic look at the truck and I guess I stripped the threads putting the new plug in and now it's helix coil time

 

ooooh boy that is dollars right there

 

Actually not too bad got a guy to do it for 250 if everything's goes to plan, got my fingers and toes crossed lol