1997 Jaguar XK8 4.0 RHD Auto Convertible.
Changes gear from 1-2-3 ok although revs seem high in each gear....
Then around 30-40 MPH the revs are now around 6.500 and seem to hold there....
The speed then will not go above 50 MPH.... just engine noise and no umph.....!
There appears to be no other rattles, shaking, etc etc...
although there is a smell of burning oil.
The gearbox oil was changed in 2018 and the vehicle has since done only 2.000 miles.... Odometer stands at 58.555.

What to check....?

 

Hi,
The Restricted Performance error mode holds the transmission in lower gear, in my car it was held in 2nd gear when this error mode occurred. Or it could be a different transmission issue affecting shifting. The best place to start is by puling the codes, this will give a clear direction as to the culprit(s), and offer ample opportunity for others to offer meaningful assistance.

But for now, not knowing anything about anything related to your car and codes, my suspicion would lie with the throttle body, where an error in the rheostat signals (input side to output side) puts the system in Restricted Performance mode, and the results you describe follow. But again, pull the codes, it will guide the investigations.

All the best,

Jerry Lippmann
2000 XK8 Conv 4.0 LHD BRG
1998 XK8 Conv 4.0 LHD BRG
1999 XK8 Conv 4.0 LHD BRG

 

If manually you can shift and bypass the situation ?