The engine runs on idle with no problem. the problem is once you want the car to accelerate. I have other engines one other cars plane helis and i can tune them with no problem. this engine does not want to be tuned what ever you do to it. i have done all settings all test...the pinch test for the low screw...i have done the test if its leaking air...etc...everything but with no change. also i have noticed that when the engine gets to running temp and when using it for some time.....the high needle adjustment screw it becomes loose and rotates on its own. HELP...its getting really annoying. It run perfectly only for a couple of days since i got it... after that.....