My wife's 2003 Odyssey starting having a surging idle, bouncing between 1000 and 2000 rpm, and generally being a handful to drive on the way home - low on power, uneven, etc.

Here is a video of what it sounds like while parked...

https://drive.google.com/file/d/0B-e...ew?usp=sharing


I have done some research through here, and it seems like it might be the IAC valve, but I really like to know what I'm going after before I start taking things apart in my unheated, non-lighted garage. (Or worse, calling my mechanic.)

 

Is the check engine light on?

 

CEL was on, and at one point the TCS and Maintenance Needed lights were on.

I got the car to the local Advance, scanned the codes - IAC, as well as some old codes from a bad ignition coil this summer. Then, the issue went away. We've got about 200 miles on it since without a hiccup.

A local Honda fella at the store suggested that it might have been low on coolant, or a bubble in the coolant line - since the IAC is near the top of the coolant circuit, it's the first to be affected by low levels.

 

My 1999 Honda Odyssey with 170K miles had this issue, and was fixed when I found a loose vacuum hose. It went to the rear valve cover. I think the hunting was the computer trying to adjust to the problem.