2011 Honda accord: doesn't idle down to normal range until engaged in reverse, neutral and in drive what may cause this.
All maintenance has been done at the dealership. The computer finds no problem or
codes. It over revs idling in park, then over revs intermittently while driving. No matter the
speed, engine temp. or the actual temp. outside. Problem didn't start until about a month
ago. I've been 3 times to the dealership and it all says no code.