If your car RPM rise and drop intermitently during drive, exhaust sound abnormal, engine vibrating harshly, RPM imbalance, it might be due to a faulty throttle body. Throttle body is a controllable valve which control the amount of air enter into the engine. When the air enter into intake manifold, it combine with petrol become a flammable air mixtures, which burns in the combustion chamber. Once the throttle body is faulty, it will easily cause the case unable to start as usual, or no response from the throttle body after starting the car and press the gas pedal, black smoke coming out from exhaust, increased fuel consumption, engine vibrating. Suggest to diagnose at workshop. In order to avoid and reduce the chances of throttle body faulty, a preventive maintenance must be done such as cleaning the throttle body especially if you are located at an area with frequent sandstorm.
Suggest to diagnose at workshop, usually the keypoints of diagnose are:
1. Use a scan tool to check if the throttle body opening angle meeting the requirement. Replace if spoiled.
2. Usually there are very less cases that the throttle body needed an replacement, most of the time a dirty throttle body will require a clean up only.
3. In most cases, throttle body should be cleaned at an interval of 20k kilometer - 40k kilometer. If your car is use in a more severe environment, can shorten the throttle body cleaning interval.