my FD does some backfires at idle. Sometimes a lot, sometimes not so many, sometimes none at all. I have changed my sparkplugs and wires, but it changed nothing. I'm guessing it might be a coil pack that's about to die... ?

my engine overheated a couple of weeks ago, but it used to do backfires before that too, so I don't think it's related.

What can it be?

 

forgot to mention the car is 100% stock

 

Check map sensor.

Check TPS readings.

See if your airpump is on.

 

Onec again I have to try and teach you all the correct terminology as many of you are wrong!
The term came from early guns firing backward into the face of the shooter. Thus the pressure goes the wrong direction.
Out the exhaust is the correct direction but should be called an afterfire.
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Backfire in an automobile engine typically results from various malfunctions related to the air to fuel ratio. Usually, backfiring occurs in carbureted engines that are running lean where the air fuel mixture has insufficient fuel. ("Running lean" is typically a sign of mal-adjusted carburetors or fuel injection where there is not enough fuel for the amount of air).
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Afterfire occurs in engines that have an emission system malfunction (air injection system diverter valve), exhaust leak or unburnt fuel in an exhaust system in which the catalytic converter has been removed. When a driver shifts up and lets off the accelerator, the engine has a moment of running rich or with insufficient oxygen. This causes an incomplete burn which causes the fumes to explode in the exhaust system.
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Backfire is through the intake. Aftefire is in the exhaust.
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So much misinformation used by people!

 

well then My rx7 does afterfires at idle, and I'm trying to fix that problem