when do air filters get changed on a 2009 Grand Marquis?
30 months or 30,000 miles whichever comes first. More frequently if you drive in dusty conditions. HTH. - Jim
Very good suggestion. I like to change mine every year for good measure. I change the Fuel Filter then too.
Search Mercury Grand Marquis Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Mercury Grand Marquis Experts