There are three engines to choose from in the XJ. At the top of the tree is the most powerful version of the supercharged petrol V8, available exclusively in the XJR. It’s exceedingly rapid but very thirsty. There’s also a slightly less potent V8 that is available on the top-spec long-wheelbase model.
The other petrol unit, a less powerful V6, is significantly slower. We’d stick with the third option, the 3.0-litre V6 diesel, which is almost as quick and far more pleasant to drive, with a lot more overtaking power. Thanks to its low-down torque, it also needs fewer revs to get going.
An automatic gearbox is standard fitment and smooth in most situations. It can be hesitant when pulling away from low speeds, however.