So I just removed all the smog stuff and ran into a little problem.... After my truck gets past operating temp it loses power and stumbles and just runs like crap... Ran like a million bucks when it was cold and about 5-10 minutes after the temp gauge stabilized.

Jump ahead a few weeks (and many triple checks) and I noticed the secondary wasn't working... Took the carb off today and noticed the brass screw, see pic, was clogged. I cleaned it really well and adjusted the secondary and now the truck runs awesome again. So the question is, what is that screw? Vacuum Jet?