Hi,
you are most likely changing the problem to be stiff as Kaustubha wrote, therefore try e.g. ode15s which should make larger steps
Regarding "loosing" data: the scope usually only stores the last 5000 data points. If the problem get's stiff, non stiff solvers like ode45 make very small steps, therefore 5000 steps may only be the very last part of your integration. Click in the scope on the very left button and uncheck the "limit number of data points".
Titus
Best Answer