This has been happening since I bought the car new in 2004. I just thought someone here may be able to tell me if it is normal or not. Whenever I turn the air on in the car it seems to pull on the engine more than any other vehicle I have ever owned. There is a substantial loss in power and the engine seems to " shudder" at idle. The dealership changed out a wiring harness in 2004 but it did nothing to fix the problem.