Hey Ralph, it's Brian; we picked up our Cats on the same day last Nov. I also had some 'teething' pain upon engine start a few months back. Engine did start sometimes, but ran super rough and no rev. Troubleshooting revealed not getting 5V at TPS, thus the ECU had no idea where throttle position was. Turned out to be an ECU connector assembly problem; not all sockets on multi-pin connector were locked into place. Definitely check connector and verify all socket barrels are locked into place properly, otherwise they will back out when connector is attached to ECU.
Regarding battery being a problem, that's a red herring IMHO; especially if engine turns over without issue. I installed similar battery: Scorpion SSTX12Q-FP.....works great, plus it's only 2 lbs!