Whenevery I start my 01 cold I hear this loud hissing of air coming from the CAI and then the idle gets real rough for a few seconds like it's going to die, then the idle races a bit and then gradually starts to come down. Only happens when the engine is cold. I thought it might be the IAC solenoid so I replaced it but it is still doing it. The oxygen sensors are original. I cleaned them, but did not replace them. Cash is a bit tight right now otherwise I would have just replaced them. The truck has 77K on it. Any thoughts what it might be?

 

Mine does that too...I'm thinking the extra cold air from your CAI may make your engine "cold blooded" because for the first few seconds after start up, the motor and ECM are in an "open loop" mode (minmal sensors).
Once the oxygen sensors and such have heated up form thier internal heaters, the ECM goes to "closed loop" and sets the tuning. At least that's how it was explained to me.
Just to be on the safe side. I'm gonna clean my IAT just to make sure there's no Air Cleaner oil on it. That's the deal on the front passenger side of the intake manifold.
BTW, when's the last time you pulled your IAC and cleaned the throttle body in there...

 

I pulled the TB and cleaned that about a month ago. Maybe I should check the IAT sensor.