There's a fuel trim malfunction. That's all I know. Why didn't your mechanic fix it?

 

He recommend that I go into a MB dealership but I know it can be quite costly (i'm running on tight budget these few months).
Do you think it'll be a good idea to go into the MB dealer for a diagnostic and to get a print out of the diagnosis and go to a non-MB dealership to fix?

 

I wonder if this is affecting my mileage per gallon. I'm running at 21.5 mi/gallon.

 

There are a half-dozen things that could be causing the problem. You listed them when you defined the P0170 code. Someone needs to troubleshoot them one at a time until they figure out what it is.

The fuel mix is likely a little lean. I only say that because the code indicates there is an air leak that is too large for the ECU to compensate for by adding fuel... as I understand it. A lean mix can be quite hard physically on the engine.

I'd take it to an independent M-B mechanic. A little cheaper but just as good, maybe better.

 

Does anyone know a good independent M-B mechanic in the Los Angeles area?

 

Thanks. I found them as you suggested: http://www.obdii.com/codes.html

 

Air leak in the gas cap. replace it.

 

MMBZ in Glendora. 626 335 2013