Hmmmm... if it wasn't happening before, and was a gradual thing, it could be what saxismyaxe mentioned. To me, it kind of sounds like the rod is bent and has been for sometime. The rod could be slightly bent, but turned in such a way that the key was working fine. So as you have been playing the horn, over time, the rod was rotating (because it’s bent) and now eventually worked its way around to a place where the key will work very slowly. Again, a tech would have to look at it to know for sure. BUT since your local guys are tied up you can definitely grab a screw driver yourself and turn the rod this way and that to see if it frees anything up. If it does, just note the position of the rod using the head (3 o'clock 4 o'clock, whatever) and just check every once in awhile to make sure it's there. This could be a quick temp. fix until you get they horn to a guy so he can take the rod out and straighten it. Again, I don't know for sure if this will work in your situation, but its worth a try, and won't really hurt anything.