Dad's favourite tool! First thing fitted on the dashboard of every car he bought. He taught me a lot with that gauge. Learnt a bit myself in later years, especially with the introduction of catalytic converters. I use a Gunsons combined vacuum and low pressure gauge. not hi tech but cheap and adequate. Suspect blocked exhaust? Tee into a vacuum source and tape the gauge to the windcreen and watch for a pressure reading as the power dies. Not suitable for a rainy day!!Fuel pressure intermittently dropping under load? Put it in the fuel line and onto the windscreen.High pressure type gauge required for fuel injection. Be very careful not to have any fuel leaks, a fire extinguisher on road test is esential. Also, tie the bonnet down with a "Bungee" cord! Any other uses? regards, Gwyn