Mercury

Same as ford escort. has a 1.9 engine. i was installing new plugs and wires as part of a tune up. the old ones are fairly white. i know that means lean fuel mixture, but what could be causing this? o2 sensor maybe? how can i check that, and what else could it be? thankyou

Well if they are white or more of a tan i wouldnt worry about it.. and yes that is from a lean condition and the o2 sensors will cause this. if your car runs fine and dosent get bad mileage i would just replace the plugs.