Not really, the IAC (Idle Air Control) sets the idle rpm, there is a way to manipulate it manually, but this would throw off the TPS (Throttle Position Sensor) readings which the engine relies on for it's values to tell the ECM the % throttle to 100% readings. Best take it to the shop for idle adjustments.
I could be wrong on the '03. But for the '06, the idle can be adjusted with a SERT. Or so I've been told.
Your correct, the SERT will allow you to change the idle. FWIW I don't know why someone would want to do that, I can't remember the magic number but there is a bottom line before you starve it for oil.