What is the reason for the unstable idle speed of the car?

Excessive carbon deposition in throttle valve and leakage of intake manifold or various valves directly affect the quality of fuel mixture and combustion effect. The valve timing is faulty, the valve timing is inaccurate, the timing belt is not installed correctly, too much carbon is deposited in the intake and exhaust valves, and the valve spring is broken. If the air intake of each cylinder is different, the idle speed will be unstable.

Unstable idle speed, high and low, is an unbalanced force in the cylinder of an automobile engine, which causes the piston to collide when doing work, causing the engine to shake and making the idle speed deviate from the normal standard range. Engine idling instability is a common fault in engine maintenance.

Solve the problems of unstable idle speed, high and low, and flameout.

Clean the throttle.

Replace the intake pipe or find the leakage position for maintenance.

Clean the fuel injector.

Check whether the air flow meter is faulty, and replace it if it is.