Fair enough, but wouldn't that throw codes for the CAT itself?RickHaleParker wrote: ↑Thu Dec 14, 2017 8:40 amit possible to have such a sudden, spectacular failure of the exhaust system
Exhaust system failures can appear to be sudden, once the condition produces enough back pressure. Material from resonators and mufflers can act like a rag getting sucked into the system.
As of now, I only have the aforementioned P0300, P0301, P0302, P0304, and now a P0102 (I disconnected the MAF and started the car to test that - no change in behavior), but I don't consider that one to be real.
It's still cold as anything here, so I haven't done much yet. I crossed my fingers for a quick fix this morning and ran across the street to Advance Auto right as they opened and bought a brand new, non-returnable ignition coil. I installed it and fired the car up. It started with a bang, but that seems to have been a one time thing (it started fairly normally tonight after work).
I THINK it ran the tiniest bit better with the new coil, but I ran out of time this morning and had to hop in the other car go to work. I was running late.
This evening, I started the car again. It didn't fight me this time and started up fairly easily. After all the times I've started it. I'm no longer suspecting that fuel supply is an issue. But, it's still running rough like it's not firing on all cylinders. After warming up a few minutes, the live misfire came back and the sulfur odor with it. So, I shut the car off and called it a night. No new codes.
This Saturday, I'm planning to run a compression test, just to see what's going on, especially with cylinders 1, 2, and 4. That'll give me a good excuse to check the condition of the spark plugs, too. Can a malfunctioning coil damage a spark plug? I'll probably also do a more detailed check on the fuel pump, relay, and may, per the suggestion above, check fuel pressure at the rail.