I have a 1991 LS400, which is having problems with something draining the battery while sitting and not running. Then when the car is driven when it is stopped and turned off it will not start again until it sits for a while. The battery has been changed several times by lexus and they can not find anything wrong with the car. Can anyone help me solve this problem because the car has close to a 100 thousand miles and is in very good shape. I plan to keep it for a while and I also plan to start doing much of the mechanical work on the car myself.