My 01 xk8 back a couple of weeks ago after a new fuel pump and water pump. Ran well on two long outings but had a power loss when climbing a steep hill at a slow start, seemed like didn't want to down shift, well I came across an old post about a throttle body adjustment and checked it, the cable was slack so I adjusted it and Eureka she is performing 110% better, now I know I'm going to get a speeding ticket for sure. Took her for a climb up a local steep road and not the slightest hesitation on the down shift when I punched it.
Thanks to those earlier who posted (Rev Sam and others) I cant believe such an easy adjustment could make so much of a change in performance
Happy Memorial Day All

 

Congrats on getting that sorted! Hope you have a great holiday as well!!

 

I did that a month ago...and the car felt like it's got additional 30hp...although like you said I did get an $800 ticket running 110 mph on the back road of Oregon to Reno ....