As brockmd said Ford uses a 5W-20 for most oil changes, however, they are now selling a 0W-20 full synthetic. You will be able to go further on an oil change and get superior protection. Just remember to use a good filter. Motorcraft has a pretty good filter. You should be ablet to go up to 10000 miles on an oil change with the full synthetic. I myself have a 2005 Focus ST with the 2.3L engine. Since I am a Certified AMSOIL dealer I use their 0W-30 full synthetic. It is rated at 35000 miles or one year when you use their EA oil filters. I started using the oil after 5000 miles on my Focus. I put around 25000 miles a year on the car. Since owning the Focus I have only had to add one quart per year between changes. Mileage has improved two mile per gallon. I average about 33 miles per gallon. I do mostly highway driving. The 3000 mile oil change anymore is a marketing ploy to sell more oil. GM has even debunked the notion of the 3000 mile oil change. More of their cars are coming out with oil monitoring systems to let you know when to change the oil. Most cars are going 7000 to 10000 miles on regular oil. In Europe most people change their oil at around 9000 miles. Hope that helps. Good luck with your new Focus. | 
