2003 2.2 petrol estate, drove it down road and heard a sort of hissing noise, rather like gas escaping and since the misses wasn't in the car at the time I assumed it was a new fault with the car.
It only happens when my foot is pressing the accelerator and the car is pulling, if foot is off pedal then sound disappears, also absent if at a standstill and engine is revved up.
The source of the noise is hard to gauge but seems to be over my left shoulder so points to something like hole in exhaust maybe, but when ticking over or revved up with car stationary there is no noticeable blow from exhaust.
If it is not the exhaust, or the missus what else could it be?