Jerome Husfelt

If anyone can offer some insight into this problem with cylinder #4 I'd be forever grateful. I removed the plug with no problem, attempted to put it right back in and now it won't thread tight. Thread doesn't catch at all. You can feel it skip over that first thread as you tighten it. some of these pics are from the affected cylinder, then one pic from cylinder 1 to show the difference. The spark plug I removed is still whole and no damage to the thread. It will easily tighten into #1, and easy to remove. Nothing fell into the shaft either. this is a 97 f150 4.6. I am baffled.






Cylinder #1





Cylinder #4

sako42

Looks to me like there is something in cylinder 4. Maybe a helicoil?
the 97 thru 2004 models are known for spitting out spark plugs which damages the threads and the fix is a helicoil. Maybe the previous owner had a plug spit out on him/her.

Jerome Husfelt

We were never informed of this when we purchased the truck in 2000. Never paid to have it done, and I have been changing the plugs myself for quite a while, but this doesn't mean it wasn't done at some point. we've had problems with fouled plugs and recently heard popping noises when accelerating. I know there's a gasket problem going on because we smoke like crazy when idling for a few minutes, also have the overheat protection kick in even though the temp reads normal...after a few restarts it stops going into limp mode. the latter problems we're dealing with, but this spark plug is really got us stopped in our tracks.

sako42

Are you replacing the plugs? If so try a different plug maybe? When I replaced mine (2005 4.6 liter) I started all the plugs with an 8" extension attached to a spark plug socket. I didn't use the ratchet wrench until I had them pretty much tightened all the way.