How To Replace the Canister Purge Valve on a Jaguar XK8 | More info
The canister purge valve is located in the left front wheel well. To get to it you need to take off the wheel and then remove the wheel well liner. (Actually, I think it's probably possible to remove it by just turning the wheel to the left and removing a couple of fasteners on the wheel well liner, but it's really easy to remove the liner, so that's the way I did it.) A bad canister purge valve will cause a clicking sound from the left front wheel well, and also you'll probably smell fuel from that area, too.