RHYTHMIC
ENGINE SPUTTERS
DEEP, HEAVY, THUDDING SOUND
NOISY PISTON RINGS
SHARP, METALLIC, RAPPING NOISE
ENGINE BACKFIRES
MUFFLED, BELL-LIKE SOUND
ENGINE KNOCKS OR PINGS
LIGHT, TAPPING NOISE
HALLOW, RAPPING SOUND
ROUGH IDLE
RAPID, CLICKING SOUND
LIGHT, DOUBLE-CLICKING SOUND