1993 Backfiring Mistery
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1st Gear
Joined: Apr 2010
Posts: 1
Likes: 0
From: Spring Lake MI
1993 Backfiring Mistery
My 1993 LT1 six speed has recently began to backfire when I downshift or let off the accelerator. I have checked for exhaust leaks but cannot find one and I'm looking for what I could do next to eliminate the backfiring. The car has 57K miles and runs like a dream, but it scares little kids and dogs as I downshift in town. What should I do?
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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Backfiring is caused by unburnt fuel entering the exhaust. Failing injectors can cause it, bad O2 sensor(s), vacuum leaks,,,anything that can throw the mixture off -- making it too rich.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Backfiring is caused by unburnt fuel entering the exhaust. Failing injectors can cause it, bad O2 sensor(s), vacuum leaks,,,anything that can throw the mixture off -- making it too rich.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
But my comment is to check the EGR valve. Check solenoid and vacuum lines while you're at it.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
Backfiring is caused by unburnt fuel entering the exhaust. Failing injectors can cause it, bad O2 sensor(s), vacuum leaks,,,anything that can throw the mixture off -- making it too rich.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
Even an intermittent/arcing spark plug (plug wire) could cause the problem.
Don't know enough about OPTI's (since I'm driving an L98), but I wonder if they can cause it too.
