I've always been told they were called idiot lights, you know the lights that illuminate on your dashboard while you're driving. Some people will tell you only an idiot would ignore them, others would say only an idiot would spend the money to have the problem fixed. I must admit I have lived both sides of the equation. One time the check engine light came on and I lost an entire motor. Another time the check engine light came on and after two days in the shop it was determined that I had a bad "check engine light sensor" So, what should you really do when those lights come on?