I cleaned/disinfected the air-con last night because I've been feeling a bit yuk on long drives, but only when the roof is up. Also, I rarely use the air-con, just fresh air with the heater set to mid-point. I used an aerosol from Halfords which releases nasty chemicals into the car with the air-con on full whack while re-circulating the internal air. It's too early to say if this has made a difference, more of an attempt to solve the problem by elimination. There's no hint of a leaky exhaust or crank-case oil-vapour. My commute involves country roads and I suppose that I could be exposed to chemical spraying, but that wouldn't explain the roof up/down. I was wondering if anyone else out there in Copenworld has had problems of this kind. I've only had the car a few months and don't know much about its past life, climate, storage, flatulent previous owners! etc.