2014 cx-5 2.5l fwd 107k miles. Within the last 5 months or so, the gas mileage on my cx-5 has been dropping. Was consistently at 29mpg for over a year but now it's down below 28 and continues to drop. Also within that same time frame, it has started consuming oil. Not sure exactly how much, but dealership said it was "extremely low" several weeks ago. I had been changing the oil myself every 5k miles and it was never low. Dealership changed the oil and replaced #1 ignition coil. I replaced all the spark plugs soon after. MPG is continuing to drop. My first thought was a bad PCV valve but I checked it per Mazda instructions and it passed. What else could be causing these symptoms? Or could the PCV valve still be bad even though it passed?