i have my stock traxas nimh for my rustler for almost 5 months now and i think it finally died on me... BUT WAIT!! when ever i charge it in my charger it goes normally, but when i run it in my rustler it runs extremely slow, like its the end of the batterylife but it runs for a long time... is there just some bad cells?
Have you tried another battery?
if it was a NiCd it would of looked like very bad memory had build up. but as it is nimh have you tested the voltage fresh off the charge. just to see if a cell has died.