On a serious note, has anyone thought that the valve is stuck open due to lack of vacum. The pipe goes to the rubber pipe goes to the fusebox (i know that sounds wrong) and then to some sort of resevoir and then to the manifold. My point is if this pipe is perished (lets face it most of our cars are getting on) would this effect running as is would be letting unmeterd air into the manifold, just a thought as my 2.0 litre in my opinion lacks low down torque when pulling away and a pig to drive in town traffic for any length of time, but sounds nice and runs perfect under normal driving conditions