2007 BMW 328i N52 Code 2A82 P0012

Only problem was when the car started the RPM is not satiable for 5 seconds after the car runs fine. Please don't replace anything before you check. On the 2006 down the dealer will recommend you change too many parts.  The  car was running fine no check engine light. It just the oil leak on the valve cover side(is the comment problem) of the exhaust side. After replace the valve cover gasket and road test the car on the freeway for 30 minutes. The service engine light come on and put the scanner. The code was 2A82 VANOS Intake (P0012 Camshaft position - Timing over-retarded (Bank 1) (PLAUS)). I erase the code and test drive the car the light came on again same code. After that we put a lad scope to check the camshafts and crankshaft single they good.  We check on the timing mark first everything was on the right position and put the smoke machine to see if any vacuum leak and there was no vacuum leak. we also do a redactor pressure test and the test came out good. Still looking for the problem.