I just finished replacing the left upper timing gasket cover and the valve cover gasket on a 2006 X5 4.4. Unfortunately, after putting everything back together is has a rough idle and the SES light is on. I've checked over all the electrical connections and vacuum lines and everything seems to be in order. Does anyone have any thoughts on what may be going on? Does it need to be run for a little while for the computer to properly learn everything given the battery was disconnected for 4 days and so many connections were undone? Perhaps, one of the sensors has gone bad? Any thoughts would be greatly appreciated.

Thanks!