Car is very sluggish when putting in drive. barely goes over 20mph.

Hello, when you get warning messages like you have, with symptoms that you have -- it is necessary to have the information inside the engine's processor extracted with a suitable diagnostic tool. This information will help a technician troubleshoot a more specific area of concern so that the cause of the problem can be found. The engine operates in a "limp" mode so you can get to safety, but not drive the car as normal until the problem is diagnosed and resolved.

Check the Codes, my MAP sensor was bad and my HHR felt like I was towing a trailer. Youtube, "HHR MAP Sensor," they are very easy to replace. Replace Air Filter, fuel filter, spark plugs, make sure brakes are not dragging.