I have a 2003 LTZ 4,2. I thought I had read somewhere that the car should have power at all times or it will ruin the PCM. Is this true? I've had the car since it was new. I have had some strange things happen when there's just the slightest bit of corrosion on the battery cables. I have had to replace the transmission 5 times. Could the PCM be bad? How would I know if it needs to be replaced.