Hi all, I have an 04 CTS 3.6 LSP auto. After spending a million bucks to solve a vibration issue, that was just a brake hose, all of the sudden I had a major engine vibration issue that I assumed was a misfire/bad coil- it started and ran but, like crap. Then one day I go to start it and I got nothing but the key stuck in the ignition. Bad battery, right? Took the battery for a test and charge. 99% charge no short. Still wont start. ECM? Help!