2.0 Mazda 3 started and the idle speed suddenly decreased.

2.0 The reasons for the sudden decrease of idle speed after Mazda 3 started are as follows.

1, the spark plug is not working well.

The vacuum tube is leaking.

3, high voltage line leakage.

4. The 4.PCV valve is blocked.

5. The throttle position sensor is faulty.

6, stepper motor idling fault.

7. Air leakage in the air intake system. Solution: When the engine idle speed is unstable, the idle speed should be adjusted first. If the fault cannot be eliminated after idle speed adjustment, check whether the idle metering hole and idle air metering hole are blocked. If the metering hole is blocked, clean it with gasoline or acetone and blow it with compressed air. If the metering hole is not blocked, to stabilize the engine speed at a certain speed, you can observe whether the middle and lower gaskets of the intake manifold or carburetor are leaking. If there is air leakage, it can be eliminated by fastening screws or adding or subtracting gaskets. If the idle speed is unstable and the engine power decreases, the working condition of the spark plug, the sealing performance of the valve and the ignition time should be further checked, and maintenance and adjustment should be carried out if necessary.