Hi friends Sorry for long absence. Pneumatic electro vacuum valve is fitted in 90 HP engine to do operation of variable vane of VGT turbo. When my car was new, I was getting noise of vacum realease at the time of engine off. Specific noise of air (vacum) release was sufficiently audible. But from last 20-30 K the Specific noise of air (vacum) realease is lowered now. I have to hear it with somewhat concentration. Currently odometer is showing 109000 km. And problem of poor performance has become more worse now. Is it sign of failing Pneumatic electro vacuum valve or weak vacum pump? Pneumatic electro vacuum valve is connected to rod of turbo which varies the vanes of turbo as per change of engine RPM and change in vacuum. But vane of my VGT turbo stays fully opened always. Vane of my turbo doesn't vary as per change in RPM and load on engine. Anybody can put up light on this or who has changed Pneumatic electro vacuum valve, vacuum pipes and vacum box located at backside of engine.