My car is a Fit 08 GD1

So, if i turn AC on and let the car idle, the needle bounces from 850 (being the idle rpm of the car) to 950 or so and goes back to 850 and so on...

Do you know if this is a Fit common behaviour or is something to look into?

I bought the car 6 months ago and never used the AC until now (its summer here now).

The car is in very good shape overall. My mechanic told me is not normal, but nothing to be concerned about.

What do you say?

Just happens when letting it idle and it doesnt affect at all the performance. Also, no odd sounds are coming from the compressor.

Is worth mentioning i did a serpentine belt change recently along with the idler pulley.

 

it can be your alternator cuz mine did that n now it stop

 

as the compressor kicks on and off, it's going to pull power from the motor. Normal behavior.