General troubleshooting tips for a wagging tail, these apply to all gyros not matter what make or model.

MECHANICAL
- Make sure the correct servo is being used for tail control. Too slow a servo can cause wag.
- Check to make sure that the gyro is mounted in the correct orientation.
- Make sure that the gyro is secured. A gyro that is loose will vibrate. Vibrations will cause wag.
- When mounting the gyro isolate it from the heli with a layer of foam to absorb any vibrations.
- Make sure there is no excessive slop in the tail linkage. Also make sure there isn't any binding.
- If your heli came with Z-Bends on the tail control rod, replace those with ball links.
- Headspeed that is too low can cause a gyro to misbehave.
- Check that the tail rotor grips aren't too tight. This can create excessive vibration. Vibration is bad for gyros.
- Too loose a tail drive belt can cause wag.
- Verify that tail servo is working 100% especially after any tail first crash. Damaged tail servos can cause wag.
- Verify blades are in track and balanced. Out of track or unbalanced blades can cause vibration and wag.
- Are your BOTH tail blades on right? If one is flipped in the wrong direction it can cause all kinds of problems.
- Believe or not weather can play havoc with some gyros. This seems especially true of very cold temperatures.

ELECTRICAL
- Check that the gyro is not mounted too close to an RF noise source.
- Check wiring too. "Rats nests" (excessively messy wiring) can attract RF noise that can lead to wag.
- Ensure that there aren't any wires chafing against the edges of the frame.
- Loose connections can generate RF noise.

PROGRAMMING
- Check that your gain settings are not too high. But too low will cause tail drift.
- Verify radio programming. Some radios have seperate gyro settings for idle up and normal. 
- Did you follow the set up instructions to your particualr gyro or your helis tail control?

RADIO SPECIFIC
- On the DX6 & 7 radios the GER channel is used for the remote gyro gain.