Recently my 99 m6 TA started doing all kinds of random things. The rear hatch constantly opens, the headlight motors make noise and the gauges go all crazy. Along with all that, it now won't start for hours after its been driven, it idles extremely high (when it does start) and it dies after running for a few minutes. I put a new battery in it and checked all the connections and it didnt change anything. Anybody have any idea what it could be?