Why does the cold car in mazda 6 start when the idle speed is abnormal? I want to turn it off, but I won't. I will be free for a while.

The phenomenon of unstable idle speed during cold start is related to many reasons, such as excessive carbon deposition in intake system such as throttle valve and idle valve, low fuel pressure, poor atomization of fuel nozzle and poor working performance of ignition system. On the one hand, it is directly related to the working performance of spark plugs, high-voltage lines and ignition coils; on the other hand, the poor working performance of idle speed control valves and related sensors will also lead to what you call cold start idle jitter, such as water temperature sensors and air.