Car backfire from exhaust at 50 Mph. Smooths out and back fire quites at about 65.
My car has an automatic transmission.
Hi there. There is a timing problem with your engine. Check the vacuum advance to see if its advancing when the engine is at a higher rpm. Also check the spark plugs and wires for if they are burned but functional, they can cause a delay and make the ignition fire as the exhaust valve is about to open. If you need further assistance with your engine backfiring at highway speeds, then seek out a professional, such as one from Your Mechanic, to help you.
Have a car question? Get free advice from our top-rated mechanics.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing