High Idle hell finally solved

[450slcguy]

After 2+ years of battleling with the high Idle problem, it's finally been resolved.

I tried just about every suggestion ever written about half a dozen times, with the exception of removing the intake manifold and replacing the seals.

Then one day I was tinkering around with the fuel distributor and decided to disconnect the return fuel line. I tried blowing through the line and it appeared to be clogged. After several strained lung fulls, air finally burst through and I heard a gurgle sound indicating the line was cleared.

Not thinking much about it, i didn't drive the car for several days. A few days later I took it for a drive and suddenly realized the high idle was gone. With some fine tweeking of the idle screw, it now idles steady at about 650 rpm. Been fine ever since.

Now I'd like to think that was the resolution. Nothing else was done recently to indicate otherwise. Could this have been the problem the whole time?
Not in all my reading have I heard of a clogged fuel return line as a possible reason for the high idle from hell problem.

Is there a check valve in that line? I still feel some resistance when blowing through the line, but air is getting through and thus fuel is probably returning to the tank as it should. Anyone have a similar experience?