This is a 2000 XJS with about 47K miles. This car does not get driven for long periods so the battery will discharge. In the past when that happens the car will start when the battery is re-charged. Now after not running the engine for about six months the engine will not start. Would removing the air filter box and spraying starter fluid though the throttle body be a good place to start? 

51 minutes ago, Stan Del Carlo said:

This is a 2000 XJS

I doubt that very much.

 

51 minutes ago, Stan Del Carlo said:

Would removing the air filter box and spraying starter fluid though the throttle body be a good place to start

No. Replace the battery with a new, fully charged one and then get yourself a battery maintainer and keep it hooked up when not in use.