Bit Char problems... sometimes fast, sometimes painfully slow.
 

I've tried everything, swapping 3.0 to 2.6 to ZZ motors. I've tried changing gears. But my Bit runs like crap. It will run fine and then start to stutter and barely move. I thought at first the motor contacts weren't right, but they are. I've used ZZ motors with the large contact surface and the same thing happens. Then I thought maybe the gears weren't meshing correctly. It appeared as if the motor gear was too close to the idler gear. I shimmed it back a little and it spun more freely, but that did not solve the problem!

AS of now I am out of ideas...

sounds like your battery

have you considered the supplementary sheet that tomy puts in their bits that says that the little metal tab on the end of the motor needs to be at the 3:00 position? Sometimes this changes the motor performance a lot.

if your car is stuttering it may not be the car, u may be going out of range or have a reception problem. before i modded my controller and car antenna my car stuttered too, seemed like a defect in the car when it was actually just losing reception...just a thought