Fast idle/bad mileage
 

My 2002 Tribute has been getting low MPG (I'm used to about 20 now getting 17) and has a fast idle (1200-1300). I had the idle control valve replaced about 2 years ago by a mechanic due to a VERY fast idle (5000). A mechanic buddy of mine told me he would not be surprised if it had gone bad again and to try cleaning it--no luck. After a few weeks of this, the engine light came on so I read the code. Sure enough, it said the idle control valve was bad so I replaced it with a new one. I also disconnected the battery to reset the light. My idle, though, is still the same (1300). What else could it be ? By the way, I also inspected and cleaned the throttle body. It does not look it is sticking open.