Even if I had a loading problem .. it should work fine. If it were the alternator it would give you constant starting problems. Responsible for stabilizing the engine with an overload such as Ac is the iac valve that depends on the air sensor or map / maf sensor that is in the intake. When the air sensor detects little air intake, it instructs the iac to accelerate the engine to normalize the acceleration .. if one of the 2 is failing the ride is painful. It is easy to detect that fault with a multimeter by taking the readings when you turn on the Ac. Both the maf or the iac valve have to vary their values with normal work and overload. It is an electronic problem rather than a mechanic, so a mechanic will not be able to help you. I hope it helped you.