Hi Jonathan and thanks for using 2CarPros.com. What you describe can be the result of a few things. First, when the aforementioned components are being used, there is a load on the engine that does not exist when they are off. The idle is controlled by the idle air control valve (IAC).
Here is a description of the IAC:
https://www.2carpros.com/articles/how-a-idle-air-control-valve-works
If you determine the IAC is bad, here are general directions for replacement:
https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac
Here are general conditions which can cause an engine vibrations:
https://www.2carpros.com/articles/vibration-noise
I attached a picture of the idle specifications.
Next is the idle up solenoid. When the air conditioner is on, the IACV-FICD solenoid valve supplies additional air to adjust to the increased load. This could be an issue for your vehicle. I attached a picture if its location. Additionally, there is a flow chart for checking the idle up solenoid.
If the vehicle has been tuned, I am sure your mechanic has already checked for vacuum leaks. Just in case, here are directions for finding a vacuum leak. Ask your mechanic if this has already been done. If not, start with this first.
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
If that checks good, my next step is the idle up solenoid. Follow the chart I attached below to determine if it is functioning properly.
I hope you find this helpful. If you have any additional questions, please feel free to ask.
Take care,
Joe
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Sunday, May 13th, 2018 AT 7:45 PM
