4.4 - Throttle Return Spring ( ,  )

Early models may develop a problem whereby the engine rpm will not drop to the correct idle speed. This can be caused by a dirty throttle body causing the throttle to stick ( see above ), a weak throttle return spring, or a combination of both.

Jaguar did issue a bulletin (tsb) to replace the springs on earlier models and the spring is available from dealers. If the problem persists after cleaning the throttle body, or you wish to replace it anyway, the newer part is available from the dealers.
These fitting instructions are based on the XJR model with cruise control, and so details may vary on other vehicles.

On the XJR, the throttle body is located under the inlet manifold so this must be removed first following the instructions above. Those with a ramps or a hoist may be able to gain sufficient access from underneath.

The throttle return spring is attached to the bell crank actuated by the throttle cable and is now simple to remove and replace. Ensure throttle action is smooth and that it now closes fully by pushing gently on the bell crank to ensure no further movement. Refit the inlet manifold.