RPMs staying high after using throttle

Title says it.. been running my jeep lately just at idle speed and havent really throttled her up so much so today i did..

Well the RPMs wouldnt go down after i pushed down the accelerator so i went and manually lowered it, then shut off the truck and checked all the linkages and gave them a shot or too of WD40, tried again and same thing happened..

not sure where to go from here.. should i get some new throttle cables??

also, after start up my truck begins to idle at around 800 (comfortable for me) but soon after it begins to lower itself down to like 650 600 (not comfortable for me)
any suggestions on that?? or do the two go hand in hand, not really sure haha

btw to avoid confusion i have a 4.0 87

"so i went and manually lowered it"
The throttle plate is sticking open?
Take the throttle body off and clean it good. The IAC and port it goes into too.

cleaned the entire throttle body just the other day including the IAC port as well as added a new IAC sensor.

when i say manually lowered it i mean that i got out and lowered it from the throttle body.. has to be something with the cables because the butterfly is fairly smooth when using it directly w/o cables

check the return springs for tension, lube the cables with moly grease or teflon oil. if not those, may be a sensor problem.