Good afternoon all,

In regard to an 05 105k mile XJR which is currently under-performing.
It will only rev to 5k and has, as mentioned, a lack of power. When revved in neutral it simulates a rev limiter at approx 5k and if revved further the supercharger tries to drag it further up the rev range and it makes a failing mechanical noise at which point the throttle is released to save damage. Before the neutral test, during the road test, higher revs could be obtained.
Are these common symptoms of a particular type ?

Any help would be more than greatfully received.

 

That's a safety measure placed in the ECU intentionally to avoid damage; no 'R' model may exceed a certain RPM while in P or N. Now, if it doesn't do it in a gear, that's a entirely different issue.

 

Yes it is exactly the same symptoms when driving, Could it be a wheel speed sensor ( if applicable), a gearbox sensor or similar?
Update: Had the codes read this morning and both oxygen sensors came up as did fault codes P1.5.8.2 Electronic throttle monitor data available and B1.5.8.2. So will find out the oxygen sensor values and post back. The sensors voltage did move when the throttle was depressed. Both were under a volt.