hello, my Z has started to have a drain on the battery, being dead in a couple of days. And now after jumping it a few times over the past few weeks, the speedo is going crazy, and the odometer is increasing while i'm stationary , engine running! Any ideas? I am trying to find the drain on the battery with a volt meter, (probably aftermarket stereo) but not had any luck so far. can't see any blown fuses either. Its doing my pickle in!