I smelled gas/oil after driving on the highway for a while then coming to a red light with the windows up. For me, it ended up being the engine oil cooler leaking and dripping onto the catalytic converter. Pretty expensive job. Dealer quoted $1800 CAN. Probably included a new oil cooler which it didn't need, it just needed seals. Take a look at the turbo feed line that comes from the oil cooler first. That is a common leak and much easier to be replaced.