hi guys im new to the site and only 2 weeks ago i bought my first galaxy,its a r reg 2.0l petrol.when im driving it seem to have no power i put my foot down but just seems to make noise.it went for a mot on saturday and only failed on emissions.so i ordered a catalytic convertor which im waiting for.am i right thinking this is the problem.i also ordered a lambda sensor.at the moment its doing 2miles to the pound.any advice would be very helpful thanks.