Dear Doctor: We are the original owners of a 2000 Mazda Miata with 56,000 miles. Sometimes it runs rough and the “check engine” light flashes. We took it to our garage and it shows a misfire code, so we put new plugs and plug wires, but it did not fix it. Our garage says until he hears it running rough he is at a loss as to what it is. Could it be a coil? It would probably be a $500 part and labor gamble. I don’t want to change parts for the sake of changing parts and not fix the problem. What’s your advice? Walt
Dear Walt: Multiple and random misfire codes usually equal a spark problem. Ignition coils are very common on this car. Have your technician check with Identifix and also look on the Alldata web site for a history of problems listed on this car.