No, unplugging the ECU does not erase any settings. I am a CRD owner, but it appears if a lot of your issues could be attributed to grounding issues in the wire harness. Liberty's are known to develop corroded grounding points in the engine bay that can lead to all sorts of issues. Not entirely sure on a gasser, but a CRD has at least 4 ground nodes that need to be looked at, so I assume a gasser would be similar.