2007 GMC Sierra (new body style); 5.3

Cleaned the throttle body. DID NOT remove TB to clean it. After cleaning, idles high at low speed. By that, I mean when driving through a parking lot, it gets up to 15-20 MPH on its own; requires braking. City & Highway driving is no issue. When stopped at traffic light, idles at 600-700 (normal). Only after I tap the accelerator does it ramp up to 15-20 MPH on its own. I understand it may require a "relearn" period. I also understand there is a relearn shortcut (haven't tried it yet). Engine runs well. Check Engine light turned off.

How long should it take to relearn the new settings? Important note: I did manually open the TB butterfly about 1/2 inch before cleaning (no lectures, please). During cleaning, I had a volunteer press the accelerator to open the TB butterfly all the way.

Thanks in advance....