What in the work makes a spark plug wire pop off of the spark plug? When I was in Charlotte my nephew started up his Ford Explorer and the thing was missing. So I asked him to pop the hood and 1 of the spark plug wires was totally off and another was almost off. Plug them back in and it ran smooth. V6

Now I got a call from my sister and my brother in laws Eclispe has a spark plug wire loose. I4.

What makes these wires pop off the plug?

 

Usually not being seated correctly from the start. Or the top of the plug is corroded and it slides off.

 

I suggested that they replace the plugs & wires so I guess that should take care of the problem.