Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Good compression test numbers, possible timing chain slack? › Good compression test numbers, possible timing chain slack? January 23, 2020 at 3:46 am #895880 Richard KirshyParticipant ummmm I’ve only seen a single MAF installed on the air intake bellows to the throttle body. Mass Air Flow MAF Sensor on BMW 3-Series 2004-2013 Not sure what your mechanic is talking about.