backfire at idle
04-29-2018, 12:33 PM
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Teching In
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backfire at idle Hey I have a 2002 camaro z28. And 1 day I cranked it up with no problem and I was sitting to let it warm up and all of a sudden a heard a random pop out the exhaust like a gun shot. It never do it while I’m driving only when I’m at a stop light or parked and it’s always random never consistent. I changed the 02 sensor mas air flow sensor and plugs... what could be the problem
05-04-2018, 11:10 PM
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This may be the checkvalves for the AIR emissions system being stuck open. If they freeze open, they will let outside air into the exhaust manifolds and during rich warmup will cause backfires or popping. The valves are under the hood, commonly call diverter valves. Cheap to replace, Rock auto has them. Biggest problem is the threads tend to freeze onto the air tubes, and its tuff to unthread them without damaging the tubes. No room to heat them with a torch, all the wiring is nearby. The alternative is to spray AC refrigerant on the inner fitting to shrink it, and then soak the threads with penetrating oil. Worked for me, stopped my popping everytime I let off the throttle.