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.
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