2005 XKR convertible will not let me fill the tank. Filler pipe is all it will take. Appears there is a check valve, or other blockage. Took it to a mechanic, he was able to fill it up no problem so it seems intermittent. I have read many posts about issues and positioning of nozzle, different gas stations etc. Not my issue. Car just started to have this problem after over 40,000 miles of daily driving. I have a manual and have started to look at some causes but you guys are the knowledge base. Any help would be appreciated.

 

You're in the wrong XK forum, you need the X100 (1997-2006) forum.
In the meantime, have you checked for a clogged Evap canister?