Runaway RPM at startup or in neutral with foot OFF the gas pedal'

I remember having this problem about 7 to 8 years ago when i first got this
van. I fixed it, but in the meantime a lot of time has passed plus INhve
had a stroke, and recognize that my memory is more fuzzy than it was. I
cannot for the life of me remember what I did to resolve  the issue. I seem
to remember it was some vacuum issue but unable to be certain. The engin
runs good, smooth, has good power (now that I have fixed a vacuum leak on
the fuel pressure regulator hose)

I would appreciate any ideas on this. Where to look, how to start!

Thanks,

John in Alabam!!!!