High Idle start epiphany!

My '87 XJ has only had a high idle start two times.. and I just realized what the common cause was. The first time it did it I had just replaced the vacuum line that runs to the vacuum bottle or whatever. The second time it did it was last night after I had removed the HVAC controls and put them back.
It seems so obvious now that the cause of the high idle start was the vacuum having bled off when I was working on those parts of the vacuum system. This means that something like a bad vacuum motor that controls a blend door could cause a high idle start...

I might be stating something obvious here.. I realize everyone knows a "vacuum leak" can cause high idle.. but I don't think many people think of it as causing a high idle start..

If I'm pointed out something obvious I apologize..

Good point. I don't know whether it's actually 100 percent true, but it's an interesting observation, and when I think back to my old 87, it does seem in retrospect that high idle starts at least diminished after I got the (constant, repetitive, multitudinous) vacuum issues, mostly involving the front axle, sorted out.

Perfectly good idea.