2007 xj 2,7 tdvi sovereign(lwb)

serviced by main dealer religiously 252'000 miles

no engine faults
no gear box faults

when going up hills or between 35-50mph it cant seem to get the right gear or revs jump up and down and never seems to be happy at a constant rpm

sets off fine, pulls like a dream and no other faults.
looking for some ideas as to cause, I have been told it may be MAf not reading so car not reacting to right pressures but thats all a bit beyond me so please dont lose me in jargon.

thanks

 

Does this happen even after a long run or during warm-up ? There is a well-known 'hunting' syndrome at the speeds you mention whilst the transmission fluid warms up.

First remedial action is probably to reflash the TCM software. However, I don't think Jaguar ever bottomed the reason for this problem.

I have to say, you have done very well getting to 252k miles; not many get into the 200s.