Sounds like the throttle cable is sticking, remove the cowl & watch the throttle mechanism as you move in & out of gear. With the engine off, disengage the gear shift & go to the WOT position, pull back to tickover & see if the throttle returns back at the engine end, sounds a bit complicated, but it ain't.
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: See rule#5