n/m, i don't want to keep checking back.
if your car is 90's or newer, you don't have an idle set screw
you have an idle stabilizer valve, which uses vacuum control to set the idle, sort of a primitive (less powerful) cruise control
your problem is one of the following:
secondary fuel pump (pickup pump)
primary fuel pump
fuel pump relay
fuel filter (cheapest, probably $5 or less, replace this)
vacuum leak
if your car runs fine, but idles like ***, it's one of these, and if your car is an early 90's car using motronic fuel management, it may just be a dying air regulator 'flap' or a corroding relay. my 91 16v golf had a crappy idle, and after a few $100 trying to find the problem, i said to hell with it