In Summary
  • A throttle valve can malfunction when it sticks and fails to close or open on time due to mechanical damage or restriction caused by deposit buildup in the throttle body.
  • There after it does not harm to check the transmission for any electrical faults and to make sure the gearbox oil is renewed with the correct Nissan recommended transmission fluid.

Hello Paul, I have a Nissan Xtrail that seems to have a problem with the gears. It suddenly jumps from one speed to another without acceleration on my part or rev when I try to accelerate. What could be the problem, and how do I get it fixed? Joan

Hello Joan, the transmission ‘hunting’ (what you referred to as ‘jumping’) from one gear to another and the engine surging (revving up) even when you have not accelerated is one of the symptoms of a bad engine throttle potentiometer. The throttle potentiometer facilitates acceleration when you are driving, which in turn determines gear shifts.

A faulty throttle potentiometer can affect gear shift quality. It is best to first rule out failure of the throttle potentiometer with a computer diagnosis and physical inspection of the throttle valve.

A throttle valve can malfunction when it sticks and fails to close or open on time due to mechanical damage or restriction caused by deposit buildup in the throttle body.

There after it does not harm to check the transmission for any electrical faults and to make sure the gearbox oil is renewed with the correct Nissan recommended transmission fluid.