Checked your ICV? If you adjusted the idle with the throttle body stop that’s not really recommend and will explain the higher idle once it’s warmed up.
The idle is supposed to be constant and controlled by the ICV, assuming it’s working properly it acts as a secondary throttle allowing more air in. However it can’t decrease the amount of air lower than what the throttle body lets in. Which is why the idle speed will increase once warmed up if the throttle stop is open too far.
(That or something silly like what happened to me where my alternator belt snapped and the idle raised to 1500 RPM, but you’d notice that)