Td5 rev problem

Hi all new to the page. I've got a 2004 53 reg discovery 2 td5. Recently had some issues after an off road day. Alternator packed up was covered in clay. I managed to drive it home but could only feather the accelerator. If i reved it anymore it would cut out. Since then I've cleaned out all sensors and ECU and had a new alternator and charged battery. All that is sorted now. But when I drive now its intermittent. It sometimes jolts and holds the same gear and sort of kangaroos I have to let off to drive it normal again. I don't know what else to try. Any help would be really appreciated. I dont know how to explain it. I can drive to any speed if I do it gradually but if I plant my accelerator it jolts. Cheers for Any advice. Its starts runs and idles perfect. Drives perfect until it does that which is annoying