Hello, new to this forum. I hope someone can help..Need it bad...I own a 06 F-150 4.2 6 cyl. eng. 5 speed trans. Here's my question. How in the hell does a spark plug become unscrewed while your driving down the road? Not once but twice now on 2 different cylinders. One happened 6 months ago and now a different one today...Both times the plug stood attached to the wire. Now, no new plug will tighten at all..The truck only has 50,000 miles on it...Has anyone ever heard of this happening? Please help anyone with any advice at all..Thanks...Ray...

 

Ray -
I'm guessing the plugs may not have been tightened down enough to begin with and they slowly worked there way out and damaged the threads in the head as they did. Regardless, you've got damaged threads in the head. I'd try a threads chaser to see if you can clean them up enough to get a plug to achieve the required torque. If that doesn't work, you're looking at a time-cert or heli-coil repair to your head. A good shop can do this with your head still on the engine so it's not that bad a job. Sorry to hear of your problem though. Good luck.

 

Thanks Rick for the advice. I really appreciate it...Ray