2007 r56 S n14 90k miles. I have a p115c code. I had a p0141 o2 sensor code as well with it. I replaced both o2 sensors and the o2 sensor code is gone so far. I also just cleaned the maf sensor. but I still have this code and my original issue, which is low power. its not low all the time. seems to happen randomly. I think the next step is a vacuum leak test. is there a guide on how to do one of these? from what I understand is I can disconnect the intake tube from the maf sensor. and rig something up and blow cigar smoke in there towards the turbo. would the smoke make its way to the intake manifold though? I replaced my valve cover and gaskets I think like 20k miles ago so I don't think its that.

 

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