Car stalls when Genesis hooked up to OBD port

[hesermon]

This is on my LGN but I'm hoping someone has seen a similar problem and can offer some help. I plugged a Genesis into my OBD port and when I connected the power supply to the battery the Genesis would not turn on and the engine started missing and died. With the engine running, every time we touched the neg. clamp to the battery or ground the engine would start missing and then die. I've never had this happen before. When checking for codes the old fashioned way, there are no codes present. The car runs great, but sometimes at idle it has a random miss to the point that sometimes it will die. Always starts right back up and idle fine for a while. Seems to be no connection between hot or cold operating temp. Does this sound like a ECM or connector issue?