Typically this is caused by one of two things (I can think of).

1.  In the aircraft.cfg Contact point.0 the deflection angle is too high.  Try reducing it to anything less than 40 degrees.

2.  Too much weight on the front gear.  Try shifting weight back a foot and test response.  Careful not to over do it as it will affect balance, takeoff, and AoA on landing.  Play with it by moving fuel or passenger/cargo load.