E90 335d Oct 06 Saloon Power Loss

I'm experiencing a complete loss of power when attempting increase the speed of the car. Driving in a built up area you would not think anything is wrong, however get on to the bypass ( dual carriageway ) put your foot down & nothing happens? The car will reach 70 - 80mph eventually but something is clearly not right. If the car is put into sport mode the only way to change gear is by using the paddle shifts? Normally using the paddles is an option which you do not have to choose? Can anyone offer advice on this situation?

Thanks for response, I hope you are right, having it checked out tomorrow so should know more then.

The issue is now resolved, the hoses attached to the large turbo were very badly perished & once taken off had to be replaced with new ones, 4 in total I believe, whilst not good this wasn't the problem, once the hoses were off the turbo could be tested, the first test was the solenoid valves which I think assist in opening the waste gates, though please don't quote me on that. This was the problem, new solenoid valves required. The car has no extended warranty, so after speaking to a very helpful service frontman at BMW Wellsway in Bath it was agreed that BMW would offer, as way of a good will discount, to offer to share some of the cost involved in the repair. So with the BM discount & the car club membership taken into account I ended up paying £600 Inc vat, which I have to say I was pleased with as I had visions of £800 plus. The car is back to normal now & I'm very pleased with the service I received at Wellsway, I also think anyone with a similar problem should consider having a main dealer sort it out.