Idle Air Control Valve - IAC?

The Check Engine light wasn't on until TODAY! It just came on, so I don't think that was the cause. I think that is just another symptom.
The problem seems to be worse when the A/C is running. I'm in Texas so that's just about all the time. When I push in the clutch to coast to a stop the engine races at about 3K RPM until I come almost a complete stop. Then it slows to idle speed.
Another thing. When the A/C is on and at idle, like at a stop light, the engine surges to about 1200 RPM for a few seconds then slows to about 600 RPM (pretty slow), almost slow enough to die, for the same amount of time. It alternates back and forth unto the light changes and I start up. It doesn't do that when the A/C isn't on.
Thanks for your help on this. I'm stumped.

This might sound like a strange question but. Have you checked all the fuses under the hood and inside the car? And does the problem ONLY occur when the A/C is on?

4 cyl engine runs good. Sometimes rough idle. When I press the accelerator to the floor and let go, the engine dies. Error code says IAC. I have replaced the IAC. No improvement. I replaced the TPS.
Seem to work for a little while. Error code, however, never went out. Problem returned and error codes are the same.

Hi this is Justin I have a problem with stalling when putting in gear on my 1994 Ford ranger with 4.0 and with a a4ld transmission I just wondering can a iac valve can cause my problem I unbolted the valve and turn the key to on to see if it is working I didn't see it was moving I just wondering if this is my problem with stalling when putting in gear

To ASEMaster6371 so the valve inside the iac valve won't move when the key is on position no engine running plus I check the valve on ohms it reads 0.02 is this normal readings or not what's the normal readings on ohms for the iac valve. My set on 20 ohms

To ASEMaster6371 sorry for a late asponds so the readings off the iac valve is normal and also the part is bad if the shaft don't move I tried to clean it but it still don't move

Reset IAC and how to adjust AutoZone IAC it's adjustable an the factory Ford is not. I need to figure out how to reset the IAC on my truck the sequences and find out how to adjust AutoZone adjustable IAC for my 2.3. It is the $70.00 IAC.

My car normally starts at 2,000 rpm than drops to 1,000 slowly. First time today it started at 1,000 rpm than bog down quickly to 500 rpm and continued, turned it off and over again same thing happen. Trying to run diagnostic but I'm lost and can't figure it out. Sometimes when it sits for a bit and is turned on it will start normally and will drive normally, other times it just sit there and bogs down. If the vehicle is turned off and on even minutes after it will start at a low rpm again than bog.I started my vehicle today it was a bit low on gas so I thought that was my issue, filled it up and I thought the issue was fixed. But like I said when I turn off, than on minutes later it will start at a bog.