My 2006 S-Type Jaguar keep losing power and speed down to 40mp and when you shut it off and let it sit it starts and runs fine. I have done alot of work on it and a friend suggested the catalytic converter's are clogged could this be the problem? Any input would be awesome.

Hi Mark and Welcome to the Club,

Is your car petrol or diesel and what mileage has it done?

It could be the cat-con is full but there are many other things that can be at fault? Do you have an OBD2 code scanner or can you get access to one?

Cheers,

Steve

 

It is petrol Cubist and it has 190,000 miles.thank you for responding.

Hi Mark,

Good news that its not a diesel there are many more likely causes of the problems you're seeing. At that mileage its a good bet that the catalytic converter is choked and the resulting back pressure is causing the reduced performance. Best bet would be to get hold of a Jaguar specific OBD2 code reader to get the DTCs from the ECU - stay away from the iCarsoft i930 though, they have problems reading the ECU - the DTCs will confirm the root cause of your problems and perhaps save you a small fortune in the process.

Some say that catalytic converters, if this is the root of the problem, can be cleaned. Personally I am not convinced but it may be something to try. There are a number of sources on cleaning techniques/methods/services on the web and you may be able to find someone in your part of the world.

Hope this helps but I'm sure that other contributors to the forum will also provide some input.

Keep us posted,

Cheers

Thank you very much Cubist for giving me a possible answer to my problem.I have never heard of cleaning catalytic converter's but thanks to you for the resources I will check.

On 7/5/2018 at 4:58 AM, cubist said:

Hi Mark,

Good news that its not a diesel there are many more likely causes of the problems you're seeing. At that mileage its a good bet that the catalytic converter is choked and the resulting back pressure is causing the reduced performance. Best bet would be to get hold of a Jaguar specific OBD2 code reader to get the DTCs from the ECU - stay away from the iCarsoft i930 though, they have problems reading the ECU - the DTCs will confirm the root cause of your problems and perhaps save you a small fortune in the process.

Some say that catalytic converters, if this is the root of the problem, can be cleaned. Personally I am not convinced but it may be something to try. There are a number of sources on cleaning techniques/methods/services on the web and you may be able to find someone in your part of the world.

Hope this helps but I'm sure that other contributors to the forum will also provide some input.

Keep us posted,

Cheers

Thank you Cubist for your information I think I am going to take the off and see if cleaning them help. I checked into some kind f the cleaning products and the best product there is for some reason is not allowed in the U.S.A. and tI will keep you posted on the take off and clean job.

Hi Mark,

I've never tried cleaning a CC but given the cost of replacing them it can be very expensive so trying to clean them is potentially a very cheap option. The reason for writing is that I have spotted a few YouTube videos that may be worth your while checking out concerning how to clean the CC and what materials to use. A google search on Catalytic Converter Cleaning should get you at least three alternative approaches.

Let us know how you get on as my guess would be there would be a lot of interest in knowing how effective the selected treatment may be.

Cheers again,

Steve

Thank you Cubist and I will keep you posted on my out come.

Can bad coil packs cause reduced performance?

Hi again Mark,

Yes, but you should notice that one or more cylinders are not firing, engine would run lumpy. 

Cheers,

Steve

On 7/28/2018 at 12:01 AM, Mark Allen said:

Can bad coil packs cause reduced performance?

Hi Mark,

Steve has given you a clue!

I had the same problem with my Rover Sterling V6 with the 2.5 litre petrol engine, with exactly the same thing happening.  After about 6 miles the car would lose power, and being a 1999 model it didn't have a code erase facility.  My mobile mechanic could not fine the fault as the car ran perfectly well to start off with.  I asked him to take the car for a long run which he did, and immediately diagnosed the problem when the power loss started. A new coil pack sorted out the problem,

Getting a new coil pack might be easier and cheaper than a new catalytic converter.   

Let us know how you get on.

Regards,

Peter,