are you sure its in limp mode.my 1.9d cuts power after a sharp right hand corner.its caused by a build up of air in fuel system,the bubble of air moves in to the feed pipe and the computor picks this up as a fault.after stopping and restarting it resets itself.the old austin fx4 taxi did the same on left hand sharp bends but you had to spend half an hour bleeding system,if you were not quick enough to rev its socks off in neutral!