How to Replace a 2001 Ford Focus Fuel Filter | It Still Runs Although not a part of regular vehicle maintenance, there will come a time when you'll need to replace the fuel filter on your Ford Focus. Using a clogged filter can lead to serious problems, such as a burned-out fuel pump or a busted fuel line. Luckily, replacing a fuel filter is as simple as pulling the old one Best Fuel Filter Parts for Ford Focus - AutoZone Order Ford Focus Fuel Filter online today. Free Same Day Store Pickup. Check out free battery charging and engine diagnostic testing while you are in store.