Good ideas from Raidman. I started checking for vacuum leaks and found these mechanics tricks seem to work. Pinch off each hose including the one that goes to the break power booster. Spray either water or WD 40 on the hoses after the pinch test. A change in rev's was found because of hardened hoses or my problem the inside bellows of the power boost. And yes the wiring harness. Don't be too rough. It's brittle and movment makes it worse.
Stephen