Idle drops then recovers

[NibbanaBanana]

I have a 2006 Chevy Aveo with 207K+ miles, standard transmission. The car normally idles around 800rpm. Recently, when I have a lot of accessories running, (lights, fan on high, wipers, etc) when I slow down to come to a stop and push in the clutch the idle drops to around 500-600 rpm and then recovers to normal 800 rpm within a few seconds. It only started doing this recently. With no or low accessory load this doesn't happen. Other than this the car runs perfectly.

Any ideas?
Could this be a failing IAC valve?

 

[WobblyElvis]

I would say cleaning the throttle body is the first step. It might be sticking.
Here is a video that might help.
https://www.youtube.com/watch?v=GHb0g8GOojw

 

[Trav]

As the previous poster said clean the throttle body first, it cold be the IAC or TPS getting dodgy. Any codes?

 

[NibbanaBanana]

No codes. Runs absolutely perfectly besides this. And this only occurs under high alternator loads. (No AC in this vehicle.)

I replaced the throttle body sometime after 150K miles. (Probably around 170-180K miles but unfortunately I didn't write it down and can't find the receipt for the OEM GM part I paid $330 for.) The TPS and IAC are non removable components of the throttle body so they were replace relatively recently.

 

[Trav]

Try cleaning the TB if that doesn't help its time to put a scan tool on it. Don't start throwing parts at it, something like this can sometimes be a very simple thing.

 

[NibbanaBanana]

Thanks.

It's a fly by wire system. Is it safe to push the throttle plate open to get in there to clean it? Or just take it off and clean from both sides?