P0305-08, misfires in 5,6,7, and 8 cylinder.
That's just the message for the LH bank shutdown due to what looks like a (genuine) cat overheat. I'm assuming your passenger side is the LH side of the car? i.e. RHD car? With genuine overheats, either the cat material is breaking down and blocking your exhaust... or you have a combustion issue. Probably the former as you also had a possible cat efficiency code.
Maybe it is a combustion issue. Where should I start and which order? Ignition coils, spark plugs, swapping ecus, swapping mafs, etc? Are cylinders 5-8 on the driver side? Is bank 2 catalyst driver or passenger side? Forgot to clarify, this is a LHD car
Ok.. I'm confused. Bank 2 is the left side of the car, but I thought your hot cat was on the RH (passenger) side? Not really sure where to start if you have issues on both sides.
For misfires, the codes suggest: Check wiring, check fuel tank level (?), check fuel pressure, check fuel pump, check ignition coil connection, check spark plugs, exhaust hydrocarbons, etc.... So basically everything. I suppose you could swap over the motronic master and pump relays or just check for 12 volts at the injectors and coils (with key on) and do a fuel pressure check, depending on what tools you have.
I am just as confused, the cat on the passenger side (Right side of engine when standing behind the car) was the one glowing more red. They both were glowing, but one was way more apparent as you can tell in the photos.
Actually, I only see one photo showing the input into the muffler. Looks like you have the sports cat setup. Are the cats original? Now that I think about it, maybe the misfire codes are a result of the bank shutdown, not the cause. I never know which comes first.. the chicken or the egg... and I don't know if a cat overheat shuts down both fuel and spark. Maybe some professional input is required here @360trev
I think the cats are original. The Cat ECU's look like they've been replaced before, non oem. Here are pictures of the exhaust.
Perhaps you can find some way of inspecting the cat internals without disconnecting everything... e.g. sticking a (smartphone) boroscope in the oxygen sensor holes?
Cant open the pics, but if the ECU's are not original or OEM, I would guess that they are not the issue. I second pulling the sensors and examining the cats.
