My Jaguar X type 3l v6 will often not star after longer drive

Does it crank normal and not fire up or does it turn over slowly ?

When an engine runs fine for a long time, then fails to restart after having been off for a little while, there's a mechanical/electrical problem that needs to be fixed. it's very possible that this is leaking injectors that flood the engine when it's turned off, and excess fuel doesn't dissipate until the engine has cooled. Try starting with the accelerator floored; this Wide Open Throttle (WOT) action clears excess fuel. If this isn't the cause, it could be a defective engine coolant temperature sensor, faulty coils or plug wires, faulty crank or cam position sensors, or faulty EGR valve. As this is a twenty year old Jag, if the WOT start doesn't work, I suggest you have a Jaguar mechanic diagnose it. I've always found Jags to be a pain, and most mechanics avoid them.

Jaguars are finicky and you need a mechanic who really knows them.

Vapor lock? Is it an older Jag? Expert advice is called for.