Once I start truck, it’ll idle fine, sometimes low and once I drive and warn it up to normal running temp it will start idling high normally around 1500 RPM and sometimes as high as 2100 RPM. Does anyone know what could be going wrong? 22RE

 

First thought is a sticking throttle plate or sticking throttle cable.

 

I'm with old87yota. Very easy to check for. Whenever you have high idle, pop the hood, and try to close the throttle with your finger. If you can close the throttle (and the idle ends up close to spec 850rpm), you just need to look for what is sticky.

 

Failing the sticky throttle plate/cable, it might be the IACV stuck open/not closing, and providing too much air to a warm engine. Try pinching the hose off with a pair of Vice-Grips, and see if the idle drops. Once the engine is warmed up, of course.
On the other hand, upon which are 5 fingers , could it be the idle adjust screw's o-ring failed/cracked, leaking air in around the adjust screw? One way to check it might be to pull the cover screw off, and covering the hole with your thumb or a finger to seal it up good and tight. If the idle drops, bada-boom, bada-bing.
Finally, could it be the TPS out of alignment, making the ECU "think" the throttle plate is open slightly? The FSM has a quick, easy, check/align for the TPS.

I am far from being a Toyota pro, just throwing ideas out, about what controls the idle. I get so few any more...
Pat☺