have a c5 hpi in with a loss of power under load .looking back through this forum i have found i think the answer- a worn vvt hub .car has the same symptoms,rattle from top end ,no faults stored,when noise is loudest loss of power is worse.car has been to dealer but they could not fix . ordered part from local citroen dealer (v.expensive),it has now gone on back order for weeks! the customer needs his car back .maybe part is available elsewhere? any help much appreciated