My 5-speed 1992 SC300 has developed a high idle condition. I drove it and everything was fine, when I started it again later the same day it was idling much higher than normal, over 2,000 RPM. Obviously this is too high, what is the correct idle RPM?

I thought maybe a vacuum leak or something with the idle air control valve may be causing the idle issue, although vacuum is a steady 21in/Mg. I cleaned the iacv and replace a cracked connector, but it still idles high.

I would appreciate any advice or suggestions on possible causes.

Joe