My check engine light keeps coming on in my 2007 760Li BMW. I bought it used in 2015 with 70,000 miles and the check engine light came on shortly after I bought it. I returned it to the dealer I bought it from who then took it to a BMW shop to diagnosed the problem as a "Fuel Mixture Adaptation" problem. When I got the car back the check engine light was not on so I assumed the problem was resolved. About a month later the check engine light came back on. I took it to my local BMW dealer and they said the same thing, that the problem was a "Fuel Mixture Adaptation" problem and they could not tell me how much it might cost to repair. They wanted to try to diagnose the problem without giving me any idea of how much it might cost. That was unacceptable to me so I looked for another solution. The car runs fine and I only use premium gas from brand name gas stations. But the check engine light continues to stay on and I want the problem fixed once and for all. I then found a local mechanic who specialize in foreign cars. He changed the spark plugs and did a smoke leak test and said he could not find a problem. My vacuum vent valves seemed to be in good shape. But the fault codes keep coming up as P2187 and P2189. He doesn't know how to fix this problem. Does anyone have a suggestion of how to resolve this problem?