1999 Jaguar XJ8 Need for service

Engine problem
1999 Jaguar XJ8 72700 miles

My Jag would continuously stall. My mechanic determined that it was a throttle problem and diagosed the need to replace the air intake duct and seal duct. The mechanic also said that it was necessary to perform a fuel induction service.
Under what conditions is the fuel induction service mandatory and what would happen if it were not done?
Thank you