RPM problem

2008 tacoma 2.7 5 speed.. I have a problem with RPM the first issue is the rpm drops down to 600 rpm while the car is not moving and this only happens when the engine is warm enough to move even i am driving the car foe long time and then I stop the rpm will also drop down but if a start the car when it is cold everything is fine with the idle it will go up to 1500-2000 until it gets worm .. the other issue is sometimes I am on high speed when I press the clutch to shift the rpm will stuck or sometimes will keep going higher
I forgot to mention also sometimes the throttle will not respond at all I keep hitting the pedal and no response this mostly happens when i am reversing then i put it in first gear

 

Clean your throttle body, unhook the battery for a few min to clear learned memory, reconnect the battery, start it and let it idle until it reaches operating temp to relearn the idle.

 

Thank u i did clean the filter and replaced the MAF sensor as well but i checked the throttle and it was clean.. thank u for ur advise now the rpm much much better

 

Somewhere around 500-600 rpm is normal at idle after warming up.