I just installed my superchip, runing 87 tune on 91 octane. The JK is a lot more awake now and shifts and power are noticeable. But I do experience stumble and hesitation in the low rpms when the motor is cold. Once the motor is warm then there is nothing at all.

I notice stumble at between 1500-2000, once past 2000 its fine.

hmmmm?