Buick Honor has a displacement of 2.8. In 2006, the idle speed kept shaking. The throttle, carbon canister solenoid valve and spark plug were all changed, but it was still useless.

Hello, according to your description, this phenomenon in the engine is mainly related to carbon deposit, throttle body and accelerator pedal position sensor. First of all, you should check whether the engine has carbon deposits, such as throttle, air intake and fuel injector. If the carbon deposition is serious, I suggest you take these parts apart and clean them. After cleaning the throttle body, the throttle must be initialized with PP2000. After matching, you must wait until the electronic fan is started before operating the accelerator pedal. Finally, you have to teach yourself 5 kilometers. If the fault phenomenon still exists after cleaning these parts, it may be the fault of throttle body or accelerator pedal position sensor, and you can try to replace them with new accessories.