That doesn't make sense. A ground wire bolts to the engine or body sheet metal so it can be bare and touching since it's going there anyway. Any chance what you found is not a ground wire?
If the oil was causing the spark plugs to short out resulting in a misfire, that would set a diagnostic fault code and turn on the Check Engine light. You have to know which code was set to figure why the light was on.
Regardless, if the problem is solved, I'm happy to hear that.
Friday, March 25th, 2016 AT 9:40 PM