An odor like car exhaust is generated when the frig in running. Odor goes away when frig is off. Odor only on the inside. Cleaned inside completely. No odor until it starts to run again.

You didn't say what kind of unit you have, but you could have a freezer fan motor that needs oiling and it is heating up. The freezer coils are easy to access no matter what type of unit you have. Wash out with spray soap and water, and then clean you condenser coils which are much more important because if they are dirty the refrigerator will burn out the compressor. I have seen it happen and no warranty will cover a repair.