Tail Rotors Problem?
 

Are your pitch settings at low, half. and high stick correct? If so your engine is probably too rich.[img]i/expressions/face-icon-small-smile.gif[/img]

Tail Rotors Problem?
 

Like Stryper said, your engine might be too rich. Also, temperature affects the air density, and that affects your heli alot aswell. Check your instruction manual on the radio, but there should be something on the radio to fine tune the head speed by adjusting the collectice (pitch) for each flight. If your head speed is too low, the gyro might not be able to compensate. Check for binding in the controls, and make sure your gyro gain isn't too much or too low. Start out at 50%, and increase it from there. If the tail wagging gets worse, go back to 50% again, and decrease it untill it is smooth.