Any time your check engine light comes on, it requires attention as soon as possible. But if the light is flashing, you should pull over immediately because a flashing light typically indicates an engine misfire. Even if the car seems to be handling normally, continuing to drive without all cylinders working properly could lead to costly repairs or even a ruined engine.
5. You run out of gas
Keeping your gas tank at least a quarter full is a good idea—and not just to avoid running out. It can improve fuel efficiency and help ensure that your engine doesn’t suck up any debris that has settled at the bottom of the tank.
If the car jerks or shudders, pull over as soon as possible because you may be almost out of gas. If the engine dies, put on your flashers and coast toward the shoulder.