Check engine light P0170 and P0173
http://www.peachparts.com/shopforum/showthread.php?p=275424#post275424

P0170 code
http://mercedesforum.com/m_1673/tm.htm


P0170 Fuel Trim Malfunction (Bank 1) check vacuum leaks first


P0173 Fuel Trim Malfunction (Bank 2)