We have had this car for 17 years and there really haven't been many issues. However the last few weeks the battery drains and the car won' after about 3 weeks of no problem starts. The battery was replaced . Same problem after 3 weeks .We took it to the Ford dealer who replaced trhe starter , but it did the same thing after 3 weeks- It wouldn't start. We took it back to the dealer and he doesn't know what the problem is. I keep reading about parasitic battery drains , but am not knowledgwable enopugh to track down the issue. The Ford dealer is incompetent, unmotivated, or both.... Any suggestions?