Well earlier today I drove to another town about 70+ miles one way. I get halfway there and my engine started running rough when stopped at the red lights. After another 10 miles the "Check Engine" light came on so I drove straight to the local auto parts store and asked them to use there scan tool to see why my "Check Engine" light came on and they told me it was the #5 cylinder that was dead. I checked the plug wire at the plug and at the cap to see if it came off or whatever. Well the plug wire looked fine and I didn't have any tools so I drove it home. I let it cool down and pulled the #5 plug out and there was almost no gap so I regaped the plug before I put the plug back in I pulled the power wire to the coil and cranked over the engine for a few seconds to blow any crap out of the cylinder and I put the plug back in and tighten it and push the plug wire back on until I felt that click. I unhooked the negative battery terminal and turned the headlight switch on to clear the "Check Engine" light. I hooked the battery cable back up and started the engine and no check engine light.

No onto my question: What caused the plug to loose the gap I set ? Was it a clearance problem ? Or was it something else ?

 

clearance problem its hitting the piston, something in the cylinder, or a valve is hitting it

 

Just curious that it just did it yesterday because I did my tune up like a week ago and all plugs were gap correctly at 40

 

If there was something in the cylinder bouncing around, you would most certainly hear it.

That said, strange things can happen in there.....

 

That is what I thought, that is why when I pulled the plug I unhooked the coil power wire and cranked engine for a few seconds and nothing see to come out