I had initial steering problems , which I worked out via EFB. The plane now steers perfectly while taxiing . However when I apply power the plane shoots off the runway. No cross winds, no loss of one engine. 

Hi @peter sefton
Please ensure that your thrust is being applied evenly across both engines, also ensure you have disabled all AI Assists (Options > Assistance Options > PIloting).

Also ensure you do not have any conflicting bindings for the Tiller / Nose Steering Axis and Rudder Axis in the control options.

Thanks!