W208 - Jerky Rev Counter

[MotorWagon-W208]

Hi. My '99 320 Sport has developed (dont recall it doing it before) a jerky rev counter needle but only when accelerating. Engine sounds even and pull is normal. Decel is fine, as too if you blip the throttle in neutral - the needle is nice and smooth. I assume there is only one pick-up on the engine for the rev counter? but dont understand why it should make a difference when in Drive?

 

[Dieselman]

Presumably the torque is pulling the cable as the engine leans over.

 

[Tazz666]

Presumably the torque is pulling the cable as the engine leans over.

It's electronic is it not? so I would say there is a poor contact somewhere

 

[Peter T]

When I had this on my Jag XJS, the crank position sensor was dying.

As it got worse, the engine started running rough.

 

[MotorWagon-W208]

Um....torque pulling on the cable or a loose connection, but it only happens in Drive and regardless how hard or easy I pull away. Standstill in neutral and rev the engine hard or soft and everything is fine.

Where is the pick up/sensor located?