A p0300 is a random misfire. If the check engine light is flashing, that is when the misfires are occurring. Keep in mind, there are many things that can cause this code to set and doesn't mean the ECM is faulty. For example, a fuel pressure issue or engine vacuum leak can cause it.
What code did you get that is related to the ECM?
Also, take a look through this link and let me know if it helps:
Let me know.
Friday, May 12th, 2023 AT 9:44 PM