Thank you for responding to my post! I will have to check out the vaccum leak and get that fixed. I hope I can find and repair the leak quickly. If it is not a vaccum leak how do you change & where is the 02 sensor?
As far as the battery goes, we have already replaced the battery and still have the same problem. I will get a multi-meter and test it out. I have asked a few people and they seem to think by disconnecting the alarm system it would stop the short but they also said it may cause the car to not start.
I am more use to fixing older "muscle car" issues so vehicles that are mostly computerized I am clueless on.
The shop that gave me the $8k quote was a BMW dealership. They said they would have to completely remove the engine to get to the timing chain and replace it. I had looked up a DIY on it and it was done without removing it. My husband was the one that got the quote & I had called to confirm the quote & to find out exactly what they were going to do. It sounded like we were getting screwed right from the get go so I cancelled the appointment my husband had made.