I used to run 20% throttle boost but right now I'm running torque management off so I turned the boost off (I'm basically just trying to feel what the individual settings are doing). I'm also trying to gain some mpg's back.
But to answer your question, when the throttle boost was on I did not notice a change in idle. Is it possible the truck was cold? I did however noticed it shifted higher in the RPM range with throttle boost on. I think what is happening is the throttle position is not being read properly so the tranny acts a little different. What I noticed most was the ease of driving in the highway - very little pedal input needed with throttle boost on for long highway trips. I loved having throttle boost at 20% but like I said, your mpg takes a hit.
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