Check Engine light on, changed oxygen sensor before cat conv on 2004 Mercedes-Benz C230

And the light always comes on when I'm doing line for at least 20 min, but the car doesn't stalls or anything, fuel consumption is normal, cleaned the MAF and it pops up again. Any ideas

by in Naco, AZ on October 31, 2012
2 answers 8 comments
ANSWER by on October 31, 2012
what are the eng codes?
COMMENT by on October 31, 2012
P0171
COMMENT by on October 31, 2012
thats a lean code for bank 1 look for vac leak causing the problem
COMMENT by on October 31, 2012
where are the vaccum lines?
COMMENT by on October 31, 2012
seek a diag and est from a good repair shop in your area.
ANSWER by on October 31, 2012
you need to have someone look for a vacuum leak...
COMMENT by on October 31, 2012
how many vaccuum lines could be involved? or wich is the most common
COMMENT by on October 31, 2012
a few vacuum lines COULD be involved...but it usually is not as easy as a vacuum line...most likely it is some gasket somewhere in the intake portion of the engine.
COMMENT by on October 31, 2012
Gaskets sound expensive
COMMENT by on October 31, 2012
Gaskets themselves are not expensive....what may be expensive is getting them to their place!