Suzuki: Tracker 2.0 High Idle, new computer systems, fuel mileage

Question
I have an 2003 2.0 Tracker 2 Dr.  Auto..The idle system works as it should. 1600-800 rpm's after 2-3 minutes..My wife only drives two miles @ 40mph to work..It wastes more gas just to warm up..Is there anything that can be adjusted to lower the high idle speed ? Like is the IAC adjustable..

Answer
The high idle is NOT the culprit in the lower fuel mileage.  It's the temperature.  When an engine is at 0 degrees F, it requires as much as three times as much fuel to merely run than when it's warmed up to normal operating temp.  Warming it up takes way too long, and just wastes fuel.  When it's possible to have a clear windshield, drive it, it will warm up almost five times faster under load than idling.  Remember that short trips with the engine NOT warmed up should be counted as ten miles for one when calculating when to change the oil.  (That's what the new computer systems on the 2010 vehicles do)
The IAC and cold idle is a hard-wired value in the ECM, and cannot be changed without virtually reprogramming everything.