i have a 2003 807 with 92,000 miles and i get two messages up on screen 1st is unblock diesel filter 2nd is anti-pollen fault, iv had car a dealer and on diognostic machine twice (costly) they say i need new pollen filter thing that is bolted onto exhaust (about £800), car will not go above 3000rpm can anybody adivise or help! help! help! help!