What does engine backfire mean?

[StMalachi]

Backfire refers to the phenomenon of backfiring in the intake manifold. Below is a relevant introduction to engine backfiring: Causes of backfiring: Backfiring in the intake manifold is caused by insufficient fuel supply and an overly lean air-fuel mixture. An excessively lean mixture slows down the combustion speed, causing the combustion to continue until the end of the exhaust stroke when the intake valve opens. The fresh air-fuel mixture encounters unburned exhaust gases in the cylinder, ignites, and flows backward through the intake manifold, resulting in backfiring. Ignition misfiring: If backfiring in the intake manifold is accompanied by severe engine shaking, exhaust popping, and a significant drop in engine power, it is likely caused by ignition misfiring. Due to incorrect ignition timing, when a cylinder is in the intake stroke with the intake valve open and the spark plug fires at that moment, it can lead to backfiring in the intake manifold.