Hi Guys - have an issue and not too sure where to go next. I live in a small town and so far 3x "mechanics" either do not know or are not willing to touch the car.
I have an error code of P0422, which indicates I should be replacing the oxygen sensors and/or the CAT converter. What concerns me is the engine feels very hot, intake manifold included, to the point where ignition coil wiring was being melted and the blue spark plug/coil pack cover was being cooked.
Should I be looking at the turbo and making sure it is bolted on properly, and exhaust gases are flowing correctly? Or would a faulty CAT potentially foul the exhaust flow and cause excessive engine heat? Many hours of Google searches make me think it could be PCV trap, turbo bypass valve, turbo/exhaust manifold loose, air/fuel lean or rich, or something else entirely. I'm a bit lost to be honest.
Other symptoms:
- Cylinder 3 black (see photo - wiring has since been repaired).
- Fan stays on after short drives in cool weather.
- Performance when car is warm degraded.
- Idle when warm slightly wobbly.
- Air intake temperature high.
- Rich smell first start.
What I have replaced/fixed so far in the last 3 months:
- ETM repair kit.
- Turbo Control Valve and MAF.
- Heater hoses and heater core.
- Main coolant inlet pipe on back of block.
- Fuel pump relay.
- Fuel filter.
- Fuel pressure damper.
- All coolant hoses.
- Thermostat.
- Ignition coils.
- Spark plugs.
- Injectors.
I am hoping someone has experienced a similar issue and can nudge me in the right direction. Thanks in advance.