Mine never vibrated and/or hummed. I cleaned mine out really good with brake
cleaner and lightly oiled it which sort of solved the idle problem.

After a few years (4?), while on a trip, my idle shot up to 2500 to 3000 and
would not come down at all.

A new idle control valve from Bus Depot solved the problem.  This one
vibrates and hums.

In order to cover the last 500 miles home, I plugged the valve and hose that
goes from the valve to the air intake.

Randy Herd
86 GL Weekender
68 Kombi
98 Jeep Cherokee

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