Won't idle when warm

Hello all,

I'm having trouble with my 84 GTI that I can't seem to get sorted.  Here's the deal…

I drive it daily 25 miles each way to work.  On the drive in, it runs and idles like a champ, perfect.  On the way home, the same until I get about halfway home and then it won't idle at all.  Have to let it die and then start up at the last few traffic lights.  Next morning its fine again.  Doesn't drive or act funny in any way except no idle at all, of course unless I give it enough gas to keep it running.

I have checked and there are no obvious vacuum leaks, and I think those would be more of a consistent thing than what I'm seeing.  I've also tried stopping and pulling over to turn out the idle screw a bit which seems to correct the issue temporarily, but the next day, its back to the same old thing.

Any help would be greatly appreciated!

Have a great weekend!
Brian Petry
Springboro, OH,