Can a IAC valve this?

[Cessnadriver]

I have had Idle air valve problems in the past such as no starts and rough idle, etc. I've got them again on a year old IAC valve. But, it also had a surging problem going up and down between 1800-200 rpm today while runnung at a steady speed.
I wasn't driving the van, my wife was and she called me from the road, turned around and brought it right home.
It basically won't idle. It it does idle it will only do it for a short time. Turning on or off the A/C will kill it every time.
My real question is the surge. Can it be caused by the IAC?

Thanks for any help.

[wiswind]

Yes, the IAC can cause this.
You could try removing it...and spraying a small amount of WD-40 or Seafoam into it. If you look inside it...you will see a small threaded screw.
A motor drives this....to open and close a small valve. Not that this is the problem...but a very likely cause. Another, much less likely cause would be the Throttle Position Sensor (TPS), if it is completely bad, you will have a check engine light and a code for it. But I would suspect the IAC (even though you recently replaced it).

[12Ounce]

Also make sure the ac is not low in refrigerant.