today i finally got my spur gears and i put them on and i started it up and i was tuneing the engine and i got it tuned ok then it quiet when i gave it gas so i tuned it all the way rich the leaned it out from there. Now the engine still runs at a higher rpm than normal when the servo is all the way back then about 15secs later it goes to idle is it a tuneing problem or something else? Its abrand new engine about 2 weeks old. PLEASE HELP!!!!

Thanks for your help.