My spark plug wires have worked their way slightly off the coil pack lugs twice in the past few months. I notice it because the car ideals rough and accelerates poorly. You can also see the arching under the hood when you rev the engine. The arch goes from the connection point between the wire and coil pack to the engine block. Once I push the wire back into place the issue is solved.
Why is this happening? Is there a di-electric spray that I can use on the spark plug ends to prevent this from reoccuring?