2000 4.6 rough idle when cold but ok when warm

[wpatters1229]

I have a 2000 4.6 Triton and it was running just fine when starting. The normal process is for it to go to 1500 rpm and then slowly run down to just under 1000 rpm.
Now it stumbles when it tries to start and stalls. If you keep your foot on the accelerator so it can run at 1500 - 2000 rpm and let it warm a bit it is then OK.
Today I took off the throttle body and cleaned it. I see it has a throttle position sensor but nothing to adjust the rpm based on temperature. What is it that does that? Cleaning the throttle body did not do much to fix this problem.
I get no engine codes just the idle problem. What positions the idle to start at 1500 rpm and then idle down to normal idle?

 

[Billme]

This is the idle control unit for the engine..

 

[TonioBicicleta]

Rough idles at start up can mean that you need ro change oxygen sensors. But you would typically get a code for that.