Hi Paul:
I had the same problem last April.
Diesel Tsunamis can be difficult to set up so you get the throttle response that you desire, i.e. getting the engine to sound and act ‘normal’ when starting from idle.
Go to this thread and scroll down to the post by ‘selector’ and study what he (Crandell) has to say. It may seem a bit daunting at first but it does work. Make sure you record your final settings:
http://cs.trains.com/mrr/f/744/t/216137.aspx
Hope this helps.
Dave