When the car fully warms up to 160+ my idle goes up by itself to 2,000 RPMs and wont come back down.
Jan 8, 2021 at 7:40 AM
High idling
2017 SUBARU WRX
THATROGANKID
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We need to start with checking for codes even if the engine light is not on.
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
If there are no codes then we have to assume either there is a sensor that is not reading correctly or the ECM is the issue. I would suggest starting with monitoring the o2 sensor data while the engine is warming up and then when the RPM goes up.
The reason is, the ECM ignores the o2 sensor data until the engine is warm. Then it starts making adjustments based on what the o2 sensor data is saying. So if it is incorrectly saying that the engine is lean then it could increase the fuel delivery and that would raise the RPM. However, this should set a DTC because the target idle would be around 800 and it is much higher at 2,000 which means it will set a code due to the difference.
So let's start with this and go from there. The other major cause would be a vacuum leak. Here is a guide that will help with this:
https://youtu.be/4ktw1X4W_-k
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
If there are no codes then we have to assume either there is a sensor that is not reading correctly or the ECM is the issue. I would suggest starting with monitoring the o2 sensor data while the engine is warming up and then when the RPM goes up.
The reason is, the ECM ignores the o2 sensor data until the engine is warm. Then it starts making adjustments based on what the o2 sensor data is saying. So if it is incorrectly saying that the engine is lean then it could increase the fuel delivery and that would raise the RPM. However, this should set a DTC because the target idle would be around 800 and it is much higher at 2,000 which means it will set a code due to the difference.
So let's start with this and go from there. The other major cause would be a vacuum leak. Here is a guide that will help with this:
https://youtu.be/4ktw1X4W_-k
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Jan 9, 2021 at 3:17 PM
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