Theres nothing wrong with it - mines the same.

It's either heading for the ceiling at warp speed or then when I back the throttle off just one click its bouncing off the carpet.

I think the only way round it is by using a TX that has a programmable throttle ( just what I was told by a nitro heli flyer)

Still great fun though - mines kept me interested for months now, much more than my RC cars ever did