Originally Posted by http://www.greenhybrid.com/discuss/f27/35-242-miles-my-hah-may-1-2007-a-13395/

The engine air filter is pretty easy. Open the hood. Locate large black box on the driver side of the engine compartment. Use phillps screwdriver and loosen four screws holding the cover onto the airbox. The screws will unscrew from the lower airbox portion, but won't come apart from the top of the airbox cover. Which, is good, so you won't loose those screws. Then, do a little wiggle and a little maneuvering and pull the airbox cover off. You don't have to pull it out fully. Just enough to be able to reach inside and pull out the air filter. Take note of how it came out. That way, you can put the replacement filter back in the right way. There's a definite side that faces up and a definite side that goes in first. Once the new filter is in place, the reinstallation is the opposite of disassembly.