I changed the oil & filter in my 06 CS this weekend for the first time since I recently bought it. I added just over 8 quarts of new oil but even after the car sat for a long time the oil indicator was still flashing the bottom bar. I tried adding a little more over time and after 9.5 quarts it only was 2 bars above the bottom arrow. As a test I kept adding oil to see what it would take to say it was full. After 10.5 quarts the meter was at the top arrow or second from top bar. I've since drained a quart out so I'm still at 9.5 quarts and it again registers only half full. What's going on here? Could my sensor be shot? I'm not sure what to do.