Just bought my 07 mcs with check engine light on. Took it to dealer and they said needs MAF sensor. Great please replace. Well light went back on and now dealer said replace valve cover. Great do it. Damn light still on and still pulling a p115c code. Dealer cant find problem. Help.

I know have a speratic idle too.

 

You probably have a leak on the tubing somewhere. Mini issued a TSB some years ago, that the tubing where the noisemaker connects tends to crack. Check that first. You can find the various TSBs on this forum, in the Stock Problems section.

 

* MINI DTC P115C (0x2775 or 0x2B56 or 0x2B58 or 0x2B5C) - Mass Air Volume Flow 'A' Too Low
The ECU is still seeing too small of inlet volume of air passing the MAF.
Which means there could be an opening / leak after the MAF allowing unmetered air to enter the engine.

I would agree; visually inspect and if possible do a complete pressure check on the intake system.
People have seen this fault from loose intercooler tubes, to cracked / leaking components.

- Erik