Hello all.

My late 2001 XJR with 100.000 kms has developed a terrible annoying problem.

The car "stutters" under acceleration. It is most pronounced when the car has to carry some weight or uphill. The car will start accelerating, then back off, stutter for a few seconds and then pick up again.
It can readily enough kick down so it seems most pronounced in the mid range of revs.

The car has had all the ignition coils changed, the lambda probe, new sparkplugs, airfilter and radiator.

The car does not not log any errors in the cpu.

Hope somebody has an idea.

Kind regards

 

Fuel Filter is the first place I would go.

 

Then try cleaning the Mass Air Flow Sensor. Both of those steps are preventive maintenance items anyway, and won't cost you much. After that is't going to require some testing to pin down.

XJR's have a secondary fuel pump to maintain fuel pressure in higher load demand situations, and that might fit the crime. But I would be driving the car while testing with a fuel pressure gauge connected before I jumped to that conclusion.

 

I cleaned the MAF not long ago with alcohol.

All other issues has been handled by my Jaguar garage.

But all suggestions are very very welcome as I will compile them and forward them to the shop.

 

Problem solved. The problem was a defective MAF. Cleaning didn't help and the oxygen readout values were correct. But the garage changed it and the problem disappeared. So approx. $9000 dollars in repairs later I have a functional car...
(Pls. bear in mind the taxation in Denmark is way way different than in the US. A 2001 XJR is approx $100.000 here and a new XJR is around $350.000)

But thanks a lot for the great suggestions. It's cool to have such a knowledgable forum in the backhand :-)

 

Remind me not to move to Denmark anytime soon. Looks like Canada is back to the top of the list.

 

And we think our taxes in the US are bad....