Misfire
When combustion fails in a cylinder. Caused by spark, fuel, or compression issues.
Why it matters
Frequent misfires on one cylinder usually point to coil packs or spark plugs. Misfires under load can indicate fueling or compression issues.
What to look for
Misfire counters per cylinder. A single cylinder accumulating misfires likely has a coil or plug issue. All cylinders misfiring suggests fuel or compression.
Related terms
How many degrees before the piston reaches top dead center the spark fires. More advance = more power, but too much causes knock.
When the ECU detects detonation (uncontrolled combustion), it pulls ignition timing to protect the engine. Any amount above 0 degrees means knock was detected.
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