The same thing that has gone wrong for a few owners of this same model and year: the engine stalls randomly, putting you in serious peril as all systems go dead.
This problem was supposedly resolved by a recall of the throttle body, but this has done nothing to resolve the problem, and when contacting the dealer and Jaguar, it's quite amazing to what extent they go to lose an otherwise loyal customer.
I love the looks of the Jaguar, but will not buy another as I cannot understand how they can call it a prime vehicle, and then tell me that the solution to my problem is to replace the engine? At merely 82,000 on a V8 engine?
Truly disappointing to say the least.
It looks and drives nicely, but after merely nine years of driving at an average of 9,000 miles per year, it seems to be falling apart rather badly, which is something one would not expect from a high priced vehicle.
I will agree the 1999 XJ8 does have issues that it shouldn't for the price. I purchased one used with 55,000 miles and have not had a problem, yet now it has 59,000 miles, but I have done all the preventative maintenance and had the timing chains tensioners and assembly rebuilt.
Anyone can buy a Jaguar, but not everyone can afford one. That's why they really are toys, not daily drivers.
I love mine; it has more class and power than a 7 series BMW, or other competitors of its year, but it gets beat with reliability hands down.
I believe Ford will do a better job with that, even though everything ends up looking like a Taurus.