hello all, anyone now about HDI turbo,s ive got a C5 2.2 its got 157000 on the clock and uses no oil and up to now starts on the button and very reliable should be i think 136 bhp or something like that, the issue is just lately it doesent seem to want to go, im wondering if its soot build up in the VV turbo ? or one of the valve avtuators to the turbo.. any help on this guys,

thanks
Andy