Hi Richie, sorry mate, not been on here for a while! Don't think it's using more fuel. My misses hasn't moaned about having to put loadsa petrol in it!! The Mot isn't due till next year. I'll have to look at the manifold and cat at the same time i reckon. As i said, i've replaced the rest of the system so i suppose there's not a lot else it can be really! Cheers for the replies! Much appreciated!