Problem with Champion One Piece Plugs?
On my 2005 Mustang GT I recently replaced my original Motorcraft plugs with 8 new Champion one piece plugs gapped at .045. Got the old plugs out without breaking any apart. About two weeks later I went on the road for a 1600 mile trip, and the problems started.
- Check Engine light for misfire on cylinder 5 - not sure if its a bad plug or a coil problem.
- Car runs very badly sometimes at low speeds. Rough idle. Light acceleration feels like there is no power.
- Much louder "popping" from the exhaust when you rev up the engine and quickly drop off the throttle. It sounds very rough (not a pleasant sound).
- Gas mileage on the trip was 24.6 average for over 1600 miles. Most driving was at speed limit plus about 4-5 mph.
Are these Champions any good, or should I go back to the two piece Motorcraft plugs? I can replace the number five Champion plug, which might be bad, or I could just put a new set of Motorcraft in.