Q: the idle surges when it comes to a stop or is in park

I would need to know more information about the year, make, model, and engine of the vehicle for more precise help since the car surging could be caused for a number of reasons. The Check Engine Light is the first thing to check in this scenario. Any codes that come up will help in diagnosing the problem. However, since you are only seeing this when the car is parked or stopped, you may want to check if the problem is only occurring with the AC on. This could indicate that a problem within the AC is putting a load on the car that the vehicle is trying to compensate for with higher idle while the vehicle is not in motion. If you want to have this looked at, a technician from YourMechanic can come to your home or office to diagnose your car’s surging issue and verify any repairs that need to be made.