After driving for five years, the idle speed of the car is high and low.

1, the stolen goods produced in the air and the sludge produced by gasoline are easy to cause the vehicle throttle to be too dirty and the idle motor to work badly.

2. Too much carbon deposit will easily lead to lax valve closing, poor nozzle atomization and insufficient combustion.

3. The exhaust pipe is blocked, resulting in poor exhaust.

4. Air leakage leads to insufficient vacuum.

5, wiring aging, computer motherboard problems, this phenomenon is not easy to appear in the short term. Car owners are advised not to easily install other equipment for their cars.

6, cylinder pressure is insufficient, natural wear, this phenomenon will not appear in the short term.

Response measures:

1, when the engine idle speed is unstable, the idle speed should be adjusted first.

2. 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.

3. If the metering hole is not blocked, stabilize the engine speed at a certain speed and 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.

4. If the idle speed is unstable and the engine power decreases, further check whether the working condition of the spark plug, valve sealing performance and ignition time are correct, and make maintenance and adjustment if necessary.

Idle mechanism: The change of gas force in a cylinder (the change of gas force in one cylinder or several cylinders) leads to the imbalance of power in each cylinder, which leads to the inconsistency of horizontal force components of each piston during the power stroke, resulting in the imbalance of torque in the engine roll, thus causing engine jitter. It can also be said that any fault that causes the change of air force in the engine cylinder may lead to engine idling jitter.