hi all i have a 03 1.9tdi ghia 115bhp galaxy recently my galaxy is losing power whilst driving and i noticed smoke billowing from the underside of the car,at first thought had exhaust problem but noticed at rear of vehicle is a rectangular box with a pipe coming out of it which is billowing smoke (approx near rear wheel) any help please what is this box and its function and is it possible the maf would cause this problem cheers dave