Idle fluctuating
 

Without heat or anything on my idle jumps around. Cars 2017 brz with 20k. Bought it used and just noticed this. I do have an after market greedy exhaust. Assuming it’s a vacuum line or something. Common hoses that come lose or anything?

Is you car showing any trouble codes? If so, what is it?

Have you had the battery disconnected recently? If so, it could be the ECU just relearning - it will settle down.

If you have the AC ON or the dial set to defrost, it may be the AC compressor cycling - normal.


humfrz

No codes. I’d say it fluctuates 100-200 rpm. You definitely can hear and feel it.
Also no on the battery and I’m in Ohio my ac definitely isn’t on currently. I wish it was haha.

Wait so if I even have heat on defrost it’ll cause it? If so that’s my issue. I didn’t notice it till today. I’m at work now so I can’t test it out.

When you have the defrost ON, the AC compressor will cycle on and off, causing a slight change in the idle speed.

Why? Because the AC removes some of the moisture in the air it is circulating so the defroster will work better.


humfrz

Yep that was issue alright never noticed it so much with any other car I’ve ever had. Definitely noticeable in the brz. Thanks for the replies.

IS the car not still under warranty being a 2017?