My car makes a wierd noise (almost screeching, but a lower, rougher tone) when I start it. After shifting into drive and driving for several minutes it goes away. It does not happen every time I turn my car on, just sometimes. My check engine light also goes on after driving on the highway. It will eventually turn off, but as soon as I go onto the expressway, it goes back on. Please help! I'd like to have an idea of what costs I may be getting into.