can a bad coil or coil wire cause backfiring? When i pulled the coil wire of there was a bunch of black powder in the boot could this be my problem? Any help would be apreciated.

 

It could. If full spark isn't getting to the plugs. Could also do other bad things that the computer would try to correct for. Any codes when this happens?

 

I dont have a code reader yet. It does not happen constantly just every so often and more when the engine is warm.

 

Any other opinions?

 

check the heater wire to your o2's. I had a blown heater wire fuse which caused a stumble & slight backfire a few years back... worth a look. the other thing is cam timing... if your chain is old you could have jumped a tooth.

 

check cap & rotor, mine was backfiring a lot i scanned it and got a p300 random misfire code, i took of the distributor cap and my rotor wasnt making full contact because it was broke, try checking that
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