360 CS slow down light help please

The cat is never the source of the problem (the source of the problem is unburnt fuel entering the cat) -- either you've lost some part of the ignition system (and the unburnt gas ignites in the cat and overheats it), or your injection system is wrongly adding extra fuel for some reason (and the unburnt gas ignites in the cat and overheats it). Since you have a "one bank" problem, that can be a clue as to which system is creating the problem -- I'm not specifically familiar with your ignition and injection systems, but if one can't just affect one bank, and not the other, that would rule out that system as the cause.

 

George, good advice above.

If you pull the plugs on that side you may be able to narrow it down to one cylinder where the plug colour is totally different.

Some time ago I had a coolant leak into the ope for the #8 cylinder. This caused the coil/plug to short out and the fuel for that cylinder wasn't ignited and caused the cat to glow bright red (evident in low light) and the slow down warning to register.

If you have an OBD2 reader you can probably also check for long and short term fuel trim which will indicate if the system is adding to the fuel mix to try and overcome some other problem such as a leak in the inlet side after the mass air flow meter.

I think most likely cause is a bad coil pack or plug and therefore no combustion.

Best of luck and do please post your findings in due course.

 

That's a bit of a teaser George!

Spill the beans? What was the issue?

 

Yeah! Give us the final solution. That is what this community is for. Please enlighten us.

 

That's cool. A very simple cause and solution ultimately. The biggest lesson here is probably about Nephews and F Cars but.

Glad you're sorted anyway.