Why is the engine in my Peugeot 205 racing?

As the new owner of a 1991 Peugeot 205 1.6 automatic with only 18000 miles on the clock I find that the engine is racing and therefore pulls against the brakes. It also has a tendency to want to lurch, possibly stall, when I accelerate from a standstill - say, accelerating from traffic lights etc.. Could this be a faulty automatic choke, or, more expensively, that the car needs a new carburettor? Most grateful for any advice. Best wishes, Peter