Hi Bobster, did you find out what was going on with your car? I also have a 2010 Outback petrol/LPG auto which has just started doing almost exactly what you described in your post. The only difference I get is the "bang" you mentioned sounds more like a screech (mechanical or skidding tyre) for a fraction of a second, then acceleration. Engine doesn't falter at all during this. I was thinking possible ABS or electric handbrake fault. I'd love to know if you got anywhere with this.