adjusting the idle speed

[subhelix]

Yes, my car needs to be idled down just a bit. Which we had to idle it up so it would stop stalling, but was idled up to high. Actually, I did not do it personally, but I watched the guy do it. So I know where the screw is. But should it be difficult to turn this screw? I tried yesterday, and could not get it to budge one way or the other. Now, I also saw him pull the screw out with pliers, but he did not tell me what that was for. And then I just watched him turn it when it was back in the engine. This was not at a shop or anything, but just this guy from work who was willing to help me out. So my question is, should it be hard to turn? Should I have to pull it out, and if so, what do I do there and then? Thanks in advance for any advice.