High idle RPM

2006 MAZDA 3
85,000 MILES • 1.5L • 4 CYL • 2WD • AUTOMATIC
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PCHITOWO
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I bought this car at an auction and its fuel consumption is too high. Its idle RPM is around 1,200 RPMs which is way too high. I tried to adjust the idle speed by way of adjusting a screw that is on the lever that is connected to the accelerator cable, but nothing changed. Is there anything else that i should do to try and adjust this idle RPMs? Thank you
Jun 30, 2022 at 11:21 AM
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JACOBANDNICKOLAS
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Hi,

My manual does not show the engine size you identified. Is the model year correct? As far as the idle speed is concerned, it should be controlled by an idle air control valve (IAC). Please confirm the engine size for me. Additionally, take a look through this link. I feel it will be of interest to you.

https://www.2carpros.com/articles/engine-idles-too-high

Take care,

Joe
Jun 30, 2022 at 9:31 PM
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PCHITOWO
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Thank you so much for the response. My car is a Mazda Axela which is the same as a Mazda 3 but has a smaller engine. I am going to consider the information on the link you provided.
Jul 3, 2022 at 5:58 AM
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JACOBANDNICKOLAS
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Hi,

You are very welcome, but I wasn't of much help. As far as the IAC, here is a link that explains how, in general, to service one. You may be able to get away by just cleaning it:

https://www.2carpros.com/articles/idle-air-control-valve-service

Additionally, a high idle issue can also be the result of an engine vacuum leak, so consider checking for that. Here is a link that explains how to do it:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know what you find, and although I don't have the specifics for your vehicle, they primarily work the same on all vehicles, so let me know if you need help.

Take care of yourself,

Joe

Jul 3, 2022 at 7:48 PM