Question about Mazda Protege

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Daughter bought 95 Mazda Protege LX with 4 speed automatic. When at stop, foot on the brake and with A/C on, the car shakes. Turn off a/c- no shakes. Mechanic says it is just running rough and idling high. What do you think? thanks

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  • redridge Jul 22, 2009

    We will follow instructions and let you know what the outcome was.

    1.5 4cyl eng


  • redridge Jul 23, 2009

    Thank you for the info. Will have to wait til this weekend to try your solution. Hope the motor isn't burned out, as solution is ++$$$. Do you think one could be found at auto salvage from junked protege?



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There is a device on top of the valve cover / near the thottle cable call Idle Air Control (IAC).

IAC is a small electrical motor to increase rpm (just a little) to keep up with the load.

This electrical motor can burn out or just need to be lube.

TO TEST the IAC you will need two person.

Warm up the car by driving it for 5-10 minutes.

Open the hood. locate the thottle cable. Find the end of the cable.

The IAC motor will be about 3 to 8 inches away.

With the engine running turn on the headlight and high beam.

A/C on and off

You may able to hear the gear try to adjust/trim for higher RPM to keep up with the extra load for the light.and A/C.

Try keep switch on/off the AC and lights.

You will spot the IAC.motor.

If the IAC does make an noise/attempt to do the rpm trim then you may have a good chance to save it by lube it with a lite grease.

If it does not make any sound then it's a goner.

IAC is a REALLY expensive motor. It cost over $540!

It's not logical to replace the IAC.

Please provide me the engine size of this Protege.

1.5 liter,1.6 lite or 1.8 liter 4 cyc.

I will able to get the exact price and pic to you..

You can append addition question. It will be home in 6 hours to follow up on your post.

Posted on Jul 22, 2009

  • 2 more comments 
  • Vincent_G
    Vincent_G Jul 23, 2009

    For the 1.5 liter engine. The IAC valve is over $500.

    Part No.

    Niehoff Ignition Idle Air Control Valve

    Fuel Injection Idle Air Control Valve: MPI; OE Number B596-20-660, Z501-20-660

    Warranty: Limited 3 Month*

    • Ships in 1 day


    Part No.

    Standard Motor Products Idle Air Control Valve

    Idle Air Control Valve:

    Warranty: Limited 1 Year*

    • Ships in 1 day


  • Vincent_G
    Vincent_G Jul 23, 2009

    I hope you able the open the link and see the picture of the IAC unit.

    If not then please email me.

  • Vincent_G
    Vincent_G Jul 23, 2009

    I would check around few junk yards for the price first.

    Mark sure it has OE Number B596-20-660 or Z501-20-660 stamp on the body.

    Some yard offer warranty on their part too.

  • Vincent_G
    Vincent_G Jul 25, 2009

    Any luck on locating the IAC electric motor?

    You really need two person to test it because the adjustment it make is VERY FAST.

    You may not even able to hear the worn gear move.

    Keep switching the A/C and headlight ON at the same time. The computer will instruct the IAC to increase the idle and hopefully you can detect the IAC worm gear movement.



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