Okay having an unresolved problem with a 2007 R56. Replaced engine and now getting 2b64 code on idle about every 30 seconds. Have smoke tested multiple times NO LEAKS, checked timing several times, swapped all sensors and replaced with new valve cover still having issue. When it happens my vac on intake drops for a second, fuel trims skyrocket and fuel proportioning valve rises to accommodate what it thinks is a leak. Runs and drives fine other than that, plenty of power I'm at a loss any help would be appreciated.