Unitfreebie-I have the same car and the same problem a year ago... The raw gas smell is from the tail pipe exhaust due to over rich fuel mixture condition. This condition was traced to the air cleaner assembly not sitting completely down on the MAS letting air leak in causing a rich fuel mixture.
The neck of the air cleaner assembly has a rubber ring which fits very tightly around the MAS.. a rubber lubricant spray should be applied to the rubber ring before placing the air cleaner back on.... alternately, you can use your closed fist and bang down hard on top the air cleaner area over the MAS to force the rubber ring home on the MAS.
Do not let this rich condition go for too long as the raw gas will poison the catalytic converter, but the OBDII will generate an error message before that happens - P2188 & P2190 System too rich at idle Bank1 and Bank2
You know I did that to my DD 08 Mazda 3 and it flooded Leak Detection Pump and triggered CEL. I got it fixed under warranty otherwise it would have costed $330. Not sure on CLK though, but after that I try not to overfill on any car.After further investigation about my gas smell, I found that my wife had filled the tank that day. I believe she may have overfilled the tank. After a few days of use the smell stopped. I ahd never experienced that before or since?:surrender: