About 25% of the time, especially on the first startup on a cold day, I get a smell of raw fuel near the rear 1/2 of the car. It can sometimes be smelled inside the vehicle slightly. It also occasionally occurs when the car is started after being warmed up. I've attempted to check at the exhaust but the smell disappears within about 20 seconds. I've looked for drips of fuel but found none. It only occurs when first started, not when just sitting in the driveway. I've searched some of the threads here but not found an answer. MPG is averaging around 25. 2016 Countryman S All4. Thanks for any thought.