Extremely high idle (3500rpm)

[APZak]

Hello,

My 911T has always had a high idle. It used to be about 2500rpm, but once my mechanic adjusted the points, and the car idled for a while it went up to 3500rpm. (I might have played with the linkage, or adjusting the points made the engine run better. If I raise the throttle cables by hand, the idle can go so low that the car can stall if I raise it too much. Because of this, I'm preaty sure I don't have vacuum leaks, and the idle is far too high to be caused by incorrect carburator settings. What I'm asking is, where could I adjust the cable? I only see three adjustable places in the engine bay. Could my springs possibly be worn out, and if so where can I pick up replacements? Could I adjust the gas pedal anyway? Right now I sprayed all the moving parts in the engine bay with this stuff that's like wd40, but is for rusted screws/joints. I'll let that sit a while before I adjust those screws. Is there anywhere else I should spray, and any other adjustable places? Anyone know what possibly caused this high idle? The nuts on the linkage seem too tight (that's why I sprayed them) so I doubt vibration moved them. I'm not very mechanically inclined, and I'm worried I'll set too much gas to the right/left carbs vs. the right/left carbs because there are two nuts on each side.