Jerks during acceleration (Focus 2)

The cause of jerks during acceleration may be, as in the previous case, insufficient fuel pressure in the fuel rail. The electronic engine control unit, having received a signal from the throttle position sensor about intensive opening of the valve at a large angle, tries to increase the fuel supply as much as possible, but is unable to do so due to the low fuel pressure. The causes of this phenomenon and the method of checking can be found in the subsection "Jerking at the moment of starting to move".

In addition to the above reasons, jerks during acceleration of a car with an automatic transmission can be caused by either an insufficient amount of working fluid in the transmission or a malfunction of the transmission itself.

NOTE: A vehicle with an automatic transmission may accelerate jerkily at the beginning of the first trip after disconnecting and reconnecting the battery. This is not a malfunction, since after several accelerations the electronic unit will calibrate the transmission control and gear shifting will become smooth.