Hi All...
So I'm new to Mazda's and ran into a problem that I've never seen before... Here's the issue; Whenever I put on the defroster, or the AC, my engine revs, not a lot mind you, but only when I put the fan on. It's so bad that I literally have to stand on the breaks or else I'll run into the car in front of me. It only happens when I have the defroster, or AC on, meaning I could have the fan on the face/feet setting and it's fine, but as soon as I put defroster, of feet/defroster, or AC I'm literally in a car that can and has driven itself without the need to put my foot on the gas at all.

Has anyone ever had this issue or come across it before? Any lead in the right direction would be insanely greatful.

Thanks!

 

First off welcome to the forums!! Second please put your vehicles info in your signature, makes it easier for all of us since we dont have to ask what your driving. Ok so first question is what are you driving? My first thoughts are the idle air control valve is plugged up or sticking, when you turn your AC on the computer sends a signal to the IAC valve to let more air in to raise your RPMs so the engine does not stall with the added load. If its not working right it will mess up your idle and possibly give the symptom your describing.

 

Hi, sorry still learning the website and you're right, I probably should have at the very least mentioned what I drive lol. I own a 1998 Mazda 626 Es V6. I don't know if that changes anything about your response but I appreciate the info ill have to check that out.

 

If you look here http://allmazda.net/epcimg/EG5/EG57451.GIF you will see the IAC valve under the throttle body, its the large housing on the bottom with the solenoid on the right side BUT this may not be how it is installed, the IAC could be on the top in the car, you just have to look closely for it. Also unlike most IACs I know of (mostly Fords) Mazda runs coolant through theirs so you will need a new gasket when/if you remove the valve. What you can try is to unplug the wire harness going to the IAC and then try your AC, if it does not want to run away from you then you know its the IAC valve, if it still revs high then its not.

 

Ok so it appears you could be on to something with the Air Control Valve. Do you know where I can find the part at a price that won't break the bank?

Thanks for your help!

 

I just looked at napaonline, WOW that is not cheap, $400 for that thing and the picture doesnt match even BUT that could be true also since that pic is for the latest model with the V6 I could find so maybe yours is different. These are Napa's pics http://partimages.genpt.com/largeimages/817880.jpg http://partimages.genpt.com/largeimages/817881.jpg http://partimages.genpt.com/largeimages/817881.jpg

They look different than the other pic I sent so check yours to be sure. Did you unhook the plug on it to be sure it is the IAC yet? Junkyard may be your best bet on getting the part cheap, just ask about the warranty on electrical at your junkyard to make sure you can return the part if it doesnt work.

 

Sheridan, I suggest to make sure that the cheap stuff is a-ok before spending the big bucks on IAC valve.
Clean the throttle body
clean the MAF sensor
look for vacuum leaks anywhere and fix them
check the ignition system and replace ignition parts if they have aged.
Check the EGR system, clean it if needed.
Clean the IAC valve. I am sure there is a way to test the IAC valve.

If there is any small problem it could raise the idle speed just a little more than usual. Your idle speed is higher than the torque converter's stall speed.

Good luck.