2012 3.5l I Vtec - throttle body
 

P0506 DTC, clean throttle body butterfly, reassemble and now the engine hunts RPM bad. Removed thottle body again everything looks clean. Did I introduce a vacuum leak somehow, to cause my RPM hunting? On the downstream side of the throttle body there is a port that looks as though coolant has been leaking (white powder like residue remaining). Does this assembly contain the idle air control valve? If the butterfly valve does not completely close should I adjust the set screw mechanical stop to allow it to close more? Is there a procedure for calibrating (setting up) this equipment after maintenance procedures?

Is the butterfly geared? If so, you may need to replace the throttle body. Do you have a scan tool {not code reader)?

Yes the butterfly is geared. Disassembled the whole thing and the motor works good in both directions, Yes I have an Autel (AutoLink)AL519

Did you exercise the butterfly by hand? Did you use the scan tool to relearn the idle?

I did exercise the butterfly by hand. It turned out I created the difficulty by not ensuring the connector for the MAP sensor was secure. Due to having to travel for work I ended up bringing it to a shop. And they fised it up. I do remember seeing that MAP sensor DTC, post throttle body cleaning. But did not take the time to check connection integrity. If it would have said open circuit, I probably would have. Thank you kindly "grcauto" for your time and efforts.

Glad you got it fixed.

When was the last time your transmission fluid was changed ? Dirty fluid can cause the transmission to shutter