I bought a 1998 CL600 with 100k miles about a month ago. After 1k miles engines shutters at idle and low rpm accelleration. Now the temp guage doesn't seem to work or does't move much past 40. Heat doesn't get very hot either. I also noticed that gas leaks from the gas cap. I took to Autozone and got the following codes. Could this be serious? Where do I start? I'd like to find a good non dealer MB Tech N. Chicago.

cylinder #7 misfire

P0115- engine coolant temp circuit malfunction

P1147- malfunction control fuel & air

P0170- fuel trim malfunction bank 1

P0130- oxygen sensor malfunction

P0455- evaporative control system leak, emission control system leak