I use the wiper hose for my vacuum gauge. If you try and drive by the gauge, your mileage will increase, they are fun to watch. I notice my will run about 10 to 12 inches at highway speed on level ground, pulling inclines it will drop just under 10, letting off just a touch I can keep it at 10 or more. The higher you can keep it, the better the engine is working as long as you are maintaining speed.
