You are not going to be able to do much until you replace the catalytic converter. They are monitored for proper operation, and a diagnostic fault code is going to be set, and the Check Engine light will be turned on. That will cause a lot of other self-tests to be suspended. Without the results of those tests, there is almost no chance of knowing which circuit or system needs further diagnosis.
The flashing Check Engine light indicates the most serious of problems. Too much un-burnt fuel is going into the exhaust system where it will burn in the catalytic converters and overheat them. That is typically the result of spark-related misfires. A good place to start is by switching the ignition coils between cylinders that have a misfire code, and some that do not. Erase the fault codes, then see if misfire codes set for cylinder you moved the suspect coils to. You can do that with injectors too.
If you have a metal tube going to each cylinder, for the EGR system, those can cause misfire codes too. The tubes become plugged with carbon. The last one or two cylinders with clear tubes get all the EGR flow and have the misfires. The cylinders with plugged tubes get only fresh air, so they fire just fine.
Tuesday, March 21st, 2017 AT 6:31 PM