I would start with the sending unit for your fuel tank first! Remove the first aid kit from your rear parcel shelf and disconnect your sending unit. If you fuel guage goes to empty, the sender is most likely the culprit. But if not you still have a short somewhere that will have to be traced down and located. Same thing with the engine temp gauge. Also measure how much voltage you are getting at the point where the plug fits the sender to ground. this is a good place to start.