04+ GP’s won’t always throw a code when they need a CASE relearn. I learned that after changing the balancer and about 3 months later the thing started with slight misfires, that would kick off the cruise control, then progressed to the point where it would miss under heavy throttle then got to the point where it was missing all the time. The whole time I went through the plugs wires and coil packs. Finally just did a CASE relearn and it cleared ALL the misfires away.

Jeff