I have Turnigy 30A esc. I connected to DT700 motor and throttled a bit, the motor was running and suddenly after some time it started jerking.

I tested the same motor on another same ESC, the motor runs quit well.

Does any one come across this problem. Please help me out.

Regards
Nitin

What are the ESC's programmed settings ?

Do it have fail safes like brake or battery Low voltage slowdown programmed ?

Check ESC. may be some MOS blown out or solder got opened from PCB.
Dont use that ESC. Have you loaded the motor with prop while the problem starts occurring ?

Some ESCs just won't work well with certain motors.

http://www.rcgroups.com/forums/showthread.php?t=1773072

Which brand & amperage of ESC is best for a scorpion motor with a max burst current of 85amp..

try changing to factory settings for ESC.

regds