my truck just started to idle really low some times around 500 or even around 2 or 300. i have changed the fuel filter ,plugs but not the wires yet and the check engine light is on. when i reset it it runs fine for a day or so but then the light comes back on. some times it will idle fine but then other times ill start it and it just idles really low. ohh yeah and its a 2000 xlt 4x4

 

Sounds like the IAC may need to be cleaned or replaced. When the CEL comes on take it to autozone and have them scan the computer to tell you what code is being thrown.