High idle after letting off throttle

[n8huntsman]

I was getting intermittent CEL related to the throttle position sensor, P0121, on my wife’s 2011 Escalade. I changed the throttle body with an OEM AC Delco part. After changing it I attempted the relearn procedure but kept getting P0507. I’d clear it and it would pop back up. It was idling high but I told her to drive it a while and hope it got better. The P0507 finally went away and the normal idle is fine. However, when releasing the throttle and pressing the breaks it still revs as if you were still pressing the gas. It’s fighting the breaks till you come to a stop and the idle returns to normal. I’ve visually checked to make sure vacuum lines are connected. Any ideas?

[CapitalTruck]

Maybe some sort of thing that needs a Tech 2 to reset/relearn?  Just a shot in the dark.  Just for kicks, make sure all the connections are tight between airbox (maf sensor) and throttle body (and that no tears in that duct).  Though if the tear was after MAF it would probably be running lean.