2004 Ford Taurus Starting issues

The vehicle check engine light came on 5 days ago. It was still running fine. On the 5th day, it started having a delay in starting. So I took to the ford dealer to check the check engine light and find out why it is starting sluggish. The check engine light registered that I needed a new Engine Throttle. So they put one in, but did tell me the battery was registering very low. The day I picked the car up I took the battery back to where I got it 2 years ago, got a new one, put it in and the car started fine. The next day I drove to work and home. Stopped to get gas, went to start the car and nothing. Turn the key and nothing. The engine was not even cranking over. So I had it towed and this mroning they call and tell me the battery is low. The starter and alternator are registering good. Now the battery is only 2 days old. I also asked them to check any wiring that may have been knocked loose while the engine throttle was being installed. After the tow truck dropped the car off, the mechanic said he got in and the car started right up. Which makes me think there is some wiring loose somewhere. But the battery is still showing low amps. My questions are: What/where are there possible loose wires or fuses that might cause the battery to read low when it might not be? Where is the engine throttle located so I can also check for a loose wire in that area? What else could be wrong that is causing the car to drain the battery?