Like you already stated...1 check your air filter. My air filter was super dirty at 5K miles and had to be changed out...blame it on living in the high desert.
When you swap out your air filter, 2. clean your MAF sensor as well. Just be sure you don't touch the sensor with your fingers.
http://www.toyota-4runner.org/maintenance/65219-maf-sensor-cleaning-easy-video.html
While you're at it, it might not be a bad idea to 3. clean your throttle body. It's a stupid-simple job. I couldn't find a link for the 5th gen, but here's a thread on a 4th gen TB cleaning. http://www.toyota-4runner.org/maintenance/66516-4th-gen-4-0l-throttle-body-cleaning-pics.html
4. Dump a can of Seafoam in the gas tank
I'm sure some will say this is overkill, but on the flip side, you don't know how the previous owner maintained the vehicle. You're not going to hurt anything and can only benefit from doing the above. It's probably going to run you around $30 for all the stuff and about 20 minutes of your time.
IMHO, the poor mileage your're seeing is probably due to your "7 miles one way in the Burbs." I'm assuming you probably deal with frequent stops. These stops along with A/C use is probably what's killing your mileage.
When you swap out your air filter, 2. clean your MAF sensor as well. Just be sure you don't touch the sensor with your fingers.
http://www.toyota-4runner.org/maintenance/65219-maf-sensor-cleaning-easy-video.html
While you're at it, it might not be a bad idea to 3. clean your throttle body. It's a stupid-simple job. I couldn't find a link for the 5th gen, but here's a thread on a 4th gen TB cleaning. http://www.toyota-4runner.org/maintenance/66516-4th-gen-4-0l-throttle-body-cleaning-pics.html
4. Dump a can of Seafoam in the gas tank
I'm sure some will say this is overkill, but on the flip side, you don't know how the previous owner maintained the vehicle. You're not going to hurt anything and can only benefit from doing the above. It's probably going to run you around $30 for all the stuff and about 20 minutes of your time.
IMHO, the poor mileage your're seeing is probably due to your "7 miles one way in the Burbs." I'm assuming you probably deal with frequent stops. These stops along with A/C use is probably what's killing your mileage.
