Over a year ago, I got a bunch of trouble codes. Among then was P1559. I took the throttle body off, cleaned it and put it back. The CEL turned off and everything was fine for over a year. Now, It's back. Can anyone tell me what the P1559 means?

 

P1559 Idle Speed Control Throttle Pos. Adaptation Malfunction
That is your code right, you tried cleaning the TB, hopefully did a TBA. Supposedly some pins will get corroded and the IAT sensor at the back of the intake mani will fail. IF not you can try and get a TB possibly a used one if you dont wanna fork out the $$$ for a new one.