MPG (very poor) I own a 2006 L322 my MPG has suddenly gone from 20 mpg down to 15 mpg, my first thought was to change the air intake filter but found as I should have expected it was clean, any suggestions

Check your brakes aren’t dragging on the rear calipers? Will have overly hot rear discs after a run. Just an idea. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Could be a failed thermostat (failed open).....??

Andy

Try a search, I recall a thread where a sudden drop in mpg was to do with a split turbo hose or something like that. Only Range Rovers since 1988