The service engine light came on, it was on for two days and then started flashing

Hi:

There are hundreds of codes that trip the service engine light, but not many will make the light flash. Usually this is a cylinder misfire condition, caused by an intermittent ignition module or similar failed part. One thing you can do, is take your vehicle to an auto parts store, such as Autozone. Usually they will scan your code for free, and tell you what it is , or what caused it. They can suggest what part might be needed to fix it too...