I am having issues with my 04 cts. Problem is a no start and key will not turn back to lock and no gauges but power is on. If I leave key in start position, jump the starter relay, she starts and runs fine, but I have to do that, then shut off, remove key, restart as normal, all good. It will restart every time as long as you do not let it sit too long. I assume ecu is bad. I have a replacement. So do I marry my credits to original ecu and Vin, then swop out ecu and change that to car vin? Or do I need credits for both ecu's. Thanks in advance.