I as well have an 1988 XJ40/XJ6 with 95,093 miles on her.
1st thing to go was headliner.
Second problem was car shutting off on long trips in warm weather, leaving my family and I stuck on side of highway till the fuel pump cooled.
A/C blows air out the defroster vents, but not the center dash vents. Then power door locks. First front passenger, then drivers. Shortly after the drivers door handle broke. Heated of course, so $$$$.
Fuel pump went.
Tail light lens broke.
Replaced all hoses; another $$$$.
Ride leveling system comes with Stetson, because it's like riding a bucking bronco.
Hydraulic brake booster leaks down brake pedal.
And the list goes on.
We maintain it well, but keeping this kitty purring like she should is a task in itself. And I am only the 2nd owner.
I love my JAG!!! Even with all her flaws!
In the early 90' I owned an SIII. Not bad but it did have Lucas nightmares.
10.5 years ago I bought a 1990 XJ40, and for the first 7 years it had not one thing on the to-do list. The last 3 have had quite a few. From a running problem that cannot be diagnosed, to the drivers side A/C fan going bad. I have a back breaker to replace and I have it on hold. Every stop light and running light has had a bulb fault module go out. I also had the dimmer control module go bad.
One would think that Lucas Prince of Darkness was still in the car. Jaguars are great cars, but you do need to know how to turn a wrench. The problem is the brake rotor dust cover has come loose and is making a heck of a noise. Easy fix if I can ever get the caliper mounting bolts to break loose. Yes, the 90 XJ40 is one of those cars that removing the rotor isn't the easiest.
At the moment I have a love / hate relationship with it. I wish I could break the addiction.
Meanwhile my old mother keeps driving her 1985 Lincoln town-car without one darn problem. The A/C blows as cold as a refrigerator and the heater will cook a chicken.