Back when I was in college for automotive repair ( not to long ago). I cant remember the number of teachers and the number of times they said do not mess with that screw.
There is many reasons not to mess with it.
The computer when relearning or learning idle will see your lowest point say 700RPM, and say okay 700RPM, TPS 0.7V this is idle, then XRPMs and X TPS V this is X amount of speed.
Now if you change the screw and say bump the idle to 900RPM, the computer will be saying okay 900RPM, not quite idle, just gliding along, okay 900RPMs, still not on idle.
The computer will say, well okay I havent seen idle ( 700), but I have seen 900, so okay now 900 is the new idle. Okay now what have you done, now the TPS V for what should be 700, is now 900, this will mess with a lot of things.
This can mess with your TPS sensor and your computer. Driveability problems can and most likely will result.
Another thing the idle was preset from the factory, if it isnt idling correctly the proper way to fix it, is by fixing the problem, not some back alley repair.