Originally Posted by howardcano

I can only venture a guess, which is that the greater voltage drop due to the presumably higher resistance of the cheaper pack is causing the ESC to glitch. You could experiment by leaving the ESC switch off and using a receiver battery to see if that fixes the problem.

Certainly a 4WD can pull more current than a FWD, since it has so much traction.

While there is no standard way of establishing a "C" rating for a LiPo (or even its internal resistance, which is related), I can't think of any instance where a higher C rating would be detrimental to operation... so overkill may be a good idea.