This might sound stupid (im not sure) As I dont know a lot about cars aside from the basics of how to change my oil etc... Anyway! I recently had a rebuilt transmission as well as new plugs and coils put into my 2001 automatic mustang, has been running fantastic for the past month until today and my check engine light popped on. I checked under the hood to see if there was anything unusual when I noticed a wire running to one of my coils that was wired to it that I had never noticed before, not to mention it was completly new. Looks really sketchy the way it is laying across my engine and was wondering what this is for as I had never noticed it before.