yeah, the manual should have a bunch of tests you can perform with that thing. There's tests in haynes manual too. Like if you have over 20 in of vac at idle the motor is healthy...... There some tests on some online manual I had for EF's. You could also get a long vac. line and run it in to the car and get really good gas mileage. Pretty much, you wan't to have as high of vacuum as possible at all times. You'll figure out how to adjust your driving style to do so. But never let it go below 10. Also if your bogging on hills, downshift. If possible it's best to get enough momentum befor the hill so it doesn't bog.