Hi, got my first Mercedes, really nice 560SEC, but not been run much last four years. I'm hoping for help with a series of small (I hope)issues. Car drives well but:

1. temperature gauge reads less than half scale, not sure of thermostat location.

2. air pump(california spec. car) was disconnected, no belt, was that a problem for engine? Too rich reading at O2 sensor, etc? (replaced belt)

3. Pressure release from of gas tank when releasing gas cap.

4. Rubber grommet set in middle of air cleaner cover, hole in center, nothing in it.

5. rubber deflector for sun roof doesn't drop down enough when closing to clear cover, tried adjustment screws.

6. Engine surging slightly at idle speed, also a slight miss, runs fine at higher rpm, sounds like a mixture, lean, issue perhaps related to air pump?

Thanks for help in advance, I realize this is a monumental laundry list, but hopefully it won't be too daunting...

Cheers, George