My 2005 3.0l S-Type had a coolant leak that apparently got the ignition coils wet and caused misfires (P0301 & P0305) on cylinders 1 & 5. I replaced the coils and all the spark plugs and all is well - misfires are resolved. Now I am getting a P0420 code, indicating that the catalytic converter is running "below threshold". I've cleared it a couple of times and it keeps coming back after about 60kms.
Can I leave this for a while without any negative effects? The fuel consumption seems fine and I don't notice a decrease in power...
If I do eventually have to replace that catalytic converter can I install an aftermarket (like a Magnaflow) without having to replace both cats - i.e. just replace one?
Any guidance/advice much appreciated.

 

It simply delends on the exhaust emissions laws in your area.

Where I am in england the car would fail its MOT (Ministry Of Transport) test.

It wont do any further damage to the car or have any effect on how it drives leaving it.

You will likely find the after magnaflo cats are much cheaper than the genuine Jaguar ones if you need to have it replaced.

 

My car is having power problems. We thought it was the two fuel pumps, not! The starts up, has to gain enough power then it can be driven...not far. We are going to diagnose it with a scanner live data. We think that its either a senor that is causing the cats to clog or the cats are clogged and BOTH need replacing. Let us know your solution when repaired. Thank You!!

 

Anointme123 - Please don't post same problem in multiple threads! Just causes annoyance and fragmented info.

 

You have done good troubleshooting and if the code keeps coming back I would replace the cat. This code points to bank 1. Which is the drivers side in the US.

If you really don't want to replace it yet I would swap the cats from side to side and see if the code follows.

My bet is it will.

But that's a bit of work and with the age and miles you have I think you would be better off swapping it out.

It will be much cheaper to use an aftermarket one and don't forget to check the Lincoln LS since the 6 cylinder cars share a lot more parts than the V-8's did.
.
.
.

 

Thanks all. I'm going to leave it for a while if there are no adverse effects - which it sounds like there aren't. My next emissions test is in 20 months so I've got lots of time.
I think I've found a universal Magnaflow catalyst converter that I can have someone weld on when I want to replace it. I just spent a bomb having the misfires solved so I'm not in the mood for more $$$s. Will check Lincoln LS parts too...
Thanks again.

 

Running the engine with misfire will damage the 'cataverter' over time. I think the damage is done.

I used to replace 3.0 X200 and X202 'cataverters' often when I worked at the dealer. Seems like a common fault.

bob gauff