Dear Doctor: I have a 2003 Ford Ranger 4×4 with a 4.0-liter V-6 with 76,000 miles. I have had this truck since new and always used Mobil 1 Oil. For the last two years I have noticed a “ping” sound in the motor. I have changed the spark plugs with OEM Motorcraft and have filled up the tank with premium gas a few times with no change. It seems to have a pinging noise that only starts at 2,700 rpms and up. No noise below that. Can you help me? Don
Dear Don: A ping under load with a warm engine is usually a gas ping from an EGR problem, carbon buildup, poor gas quality, dirty injectors, or over-advanced ignition timing. You need to take the car to a shop that has a qualified ASE-certified technician.