Jerk at the moment of the beginning of the movement

At the moment of the beginning of the movement, there is more often an extreme case of a jerk - a failure. The most unpleasant sensations are associated precisely with the delay in the engine's response to pressing the accelerator pedal. Sometimes the engine even stalls.

A jerk occurs at the moment the throttle valve opens, when, according to the signal from the throttle position sensor, the ECU determines the moment of transition from idle to load mode and must increase the amount of fuel supplied through the nozzles. With insufficient pressure in the fuel rail, even with an increase in the duration of injection, there is not enough fuel for a smooth start. For the procedure for checking fuel pressure, see subsection «Checking fuel pressure in the power system».

In addition, a jerk can also occur due to a malfunction of the electromechanical part of the throttle assembly and contamination of the throttle valve with deposits from crankcase gases.