still having problems with my idle

Ok so my 97 2.7L with 277,000 mi. idles high. I took off the throttle body and cleaned it including removing the IAC which did not look bad. The ilde is about 300-400RPMS high. the coolant level is good but I was thinking about replacing the temp sensor anyway the part is much cheaper than an IAC valve. When I had the throttle body off there was a large amount of carbon just inside the intake where there is a port to the EGR valve. I cleaned that out also with no change in idle. anyone have any suggestions? I really do not want to throw a $160 IAC valve at if im only guessig. If I know that will fix it I have no problem doing it.

 

Was this something that was gradual or literally on the next startup?

 

Sticky throttle cable or misadjusted cable stop maybe.
Also I had a ford stuck in closed loop cycle or such, had to get some egr stuff fixed too, you might need to do more there.