The accelerator of Buick LaCrosse 3.0 is broken, which will affect cylinder 2.

1. Damage to the valve position sensor will lead to engine jitter and unstable idle speed. Because the throttle position sensor is a signal to detect the throttle opening. The engine computer adjusts the fuel injection quantity and ignition time according to the throttle opening. If the throttle valve is damaged, the engine computer will not be able to receive the signal of the throttle valve opening correctly, resulting in the inability to accurately adjust the fuel injection quantity and the ignition time. In severe cases, the engine may not start.

Second, the common faults of throttle position sensor are:

(1) Idle switch is short or open;

(2) Inappropriate installation and adjustment of the throttle position sensor leads to the idle switch not being turned off when the throttle is fully closed, or the idle switch is still turned off when the throttle has a certain opening;

(3) The sliding contact of the linear variable resistor is not in good contact, and the output signal of the throttle position sensor is interrupted intermittently during the process of the throttle valve from fully closed to fully open.