Good morning gentlemen.
GE112A and GE112B are the two first 'home racing', positive polarity cartridges that we made.
Stuttering can happen for two reasons
1 - self protection when the controller reads a current value which is greater than about 3A.
2 - broken power supply wire. Make sure that the three red/white/black wires are not broken - they may look OK on the outside but broken inside. In particular, we've seen this happen on the red (GND) cable and, oddly enough, the controller can work through the ground connection running through the car, albeit badly.
For point 1 above, if you accept the risk you may remove the protection. You will also notice an improvement in performance, but you run the risk of burning out the power MOSFETs in your cartridge. If your power supply is at most 3A per lane, then you're running low or zero risks - if you have 30A available, than things may be different.
So if you decide to give it a try, shunt the two resistors marked '050' in the back of the cartridge, near the cartridge's connector, one on each side, with a piece of wire... (the 'legs' of a capacitor, resistor, etc. will do nicely). I can't post pictures apparently, so I will give it to someone to post it for me.