have you tried cleaning out the throttle body? I know over time they can get very dirty which screws up the idle and TPS. Get some Throttle body cleaner and a clean rag. This should help??

 

The limitation 2000rpm is done by the ECU when the sub processor detects an abnormality of main processors. We call it a "Limp Home Mode". You also have codes P0171, 0420 and 0763.

The P0763 code means that the gear required by the ECM does not match the actual gear when vehicle is driven. On the other hand you also have P171 and 0420. It seems to me that your ECU is malfunctioning.

Check the ripple voltage of the ECU. You can find the way how to do it at the FAQ.

 

I will take care of this tomorrow and come back with results!