* Weak or damaged spark plugs. This can cause the engine to misfire and produce a popping or backfiring sound.
* Incorrectly adjusted valves. This can cause the engine to run improperly and produce a popping or backfiring sound.
* Damaged or misrouted exhaust system. This can cause the exhaust gases to flow improperly and produce a popping or backfiring sound.
* Vacuum leak. This can cause the engine to run lean and produce a popping or backfiring sound.
