Hello, what codes are you getting? Just a p0300? Flashing check engine light means the misfires are Catalytic Converter damaging type misfires. I would smoke test the Intake manifold, using a scan tool, check and see what the Long Term and Short Term Fuel Trims are at idle and at 2,500 RPMs, Graph the Oxygen sensors to see if any are stuck at either a high or low voltage signal. A stuck Oxygen sensor can trick the ECM into enriching or leaning out the air fuel mixture. Also with a scan tool, check to see what the g/s is on the Mass Air Flow sensor (grams per second). With any Diagnostic Trouble codes, there will be Freezeframe data, this is live data when the code actually set. Since you are obviously having hard faults right now, your best bet is to check the Fuel Trim numbers, this will tell you what the engine computer is doing and/or compensating for.
With a rich mixture and if Fuel Trim numbers are positive, I would be concerned with Catalytic Converter damage depending on how long this condition has been happening. If the Converter has melted down and is clogging up the exhaust you will have black spark plugs, major lack of power, Oxygen sensor signals that somewhat mirror each other from front to rear. This is depending on how bad the Converters are. But live scan tool data will give you a clue as to what is happening. You have a lot of miles on this vehicle, so you really need to be able to see what the engine computer is seeing from any input sensors and how it is reacting to them.
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
https://www.2carpros.com/articles/engine-has-low-power-output
https://www.2carpros.com/articles/engine-misfires-or-runs-rough
Jul 23, 2022 at 1:40 PM
