I had one of the NTs a while back, was horrible and cost me a plane. Vowed to never have one again, well bought one for a trainer for my buddy. Got er used, ran like a bat outta heck[>:]. Got a Evo .52 NX in my great planes cherokee, my lord does she move.... I think that you may have a dud like I first had. Really, I wouldnt suggest giving up, sometimes engines are a ***** to tune,[:'(] nto sure why. Treat em like a woman, some of them youll never even come close to understanding....or was that all of them. Contact horizon and see if they would replace it, you might be supprised.