I've been using this gauge for like 4 to 5 months now and I always wonder is my reading of the vacuum gauge healthy? When the car is cold let say in the morning the reading is around -0.46 bar. (note my reading is in bar not cmHg or inch/Hg) but when driving for a long time or let say the engine has reach its optimal temperature, the reading is around -0.24 or -0.22 bar which is close to 0 bar! I'm using a Toyota Vios 07 onwards model. I tap the vacuum line at the intake manifold vacuum hose...