You really need to check for fault codes. That Check Engine light is trying to tell you something important. As far as the overheating, there are MANY things that can cause that. Coolant age and level, hoses collapsing when hot and at rpm, water pump, clogged radiator, worn out viscous fan clutch (that was my problem), etc.
http://www.v12uberalles.com/pulling_codes.htm
http://www.v12uberalles.com/fan_clutch.htm