Bazza

My thoughts exactly although the hissing is such that the engine sounds like a steam engine, it only cuts in after 20 mins or so and all the hoses look sound. It seems to be some kind or resonance with one of the control valves.

Conudrum - evidence of rodent nesting within inlet manifold overnight (nuts aplenty and dead mouse), rattle in exhaust (heavily clad bend just prior to horizontal run (sorry do not know technical term for this area of the exhaust) and significant loss of power accompanied by loud hissing from inlet mainfold. Only really concerned about latter character of otherwise superb car (apart from petrol consumption - painful in UK and France). No evidence of damage to spagetti of pipework and electics surrounding the manifold area but loss of power coincident with hissing is significant (intermittant but only occurs after car has been running for 20 mins and more prevalent with heavy right foot). Enough rambling - anybody had similar problems??? BT