I have an 07 XK and recently when I go to start it there is a very brief hesitation/stumble as the engine is starting. I press the start button and it starts to roar up, sounds like it stumbles, and then continues to roar to life. The engine runs perfectly otherwise. It’s not every time, but about 50/50. I think it started once the outside temps started getting hot (80 degrees F and above). It’s not a huge deal but I am curious if anyone has seen this before. Once when it was over 90 degrees outside and in direct sunlight the engine started and immediately died. I hit the button again and it fired right up. Anyone seen this before?

 

Not that exact same problem but I've had it crank and not start, or crank then start then die.

If you have an extended warranty, take it in and see if the ECU has recorded any fault or error codes. I tend to think it's a computer issue, so the service dept. may do a software upgrade or reset to see if that cures it.

Let us know what happens!