The KV6 engine as found in the MG ZS and ZT is well known for the problems caused by it taking in its own oily fumes, this in turn clogs the secondary butterflies within the inlet manifold, this causes them to stick and also to burn the vis valve motor out, this causes a distinct lack of performance. If this has already happened then this is too late, if not by fitting one of these oil breather catch tanks you can prevent the build up of oily deposits in the manifold, this is much cheaper than £580.00 for a new manifold!