I have an '03 X-type 2.5 automatic with 121k miles and it has been stumbling on hard acceleration. The codes that are thrown include PO420 and 430 for the two cat converters, which I'm thinking of having the dealer replace, as well as PO133, PO153, PO171, PO174 & PO205. If PO133 and 153 mean that 2 of the O2 sensors need to be replaced, is that a job for a handy alley mechanic or should I have the dealer do that work too? I just don't know where those 2 sensors are and whether other things have to be removed in order to get to them. Any suggestions will be appreciated.

I was hoping to sell this car myself, thinking it's worth about $4,500 in a private sale, and replacing the cats will cost $3,000. If I can replace the O2 sensors myself for $300 or less, I might net $1,000+. The car is excellent inside and very good outside.

Thanks.
Bob

 

The ones in front do not look so bad. The aft ones look like they might be bears to get to. There are two sensors on each bank. Upstream on the manifold and downstream on the cat.
If you are going to pay to have the cats replaced just let them do the sensors too. They'll have to fiddle with the downstream sensor anyway as it is on the cat.

 

Bob - I would say the CAT and O2 sensors codes that are being thrown are a results of 1 or all of the following:

1 - Dirty MAF or it needs to be replaced.
2 - Vacuum leak
3 - Do you have the ribbed PCV hose installed on you car? If not these have a tendency to collapse or split open
4 - Bad gaskets (12) on the intake manifold.

All of these will cause issues with the CATs and O2 sensors. Your car stumble would be a results of these issues. Are you getting a "limp mode" or transmission fault" light?

I would start with the above before heading down the CAT route.

Let us know, if you have any questions about the items I listed.

Jeeves12

 

Jeeves12,

Thanks for the suggestions. I've been looking for a vacuum leak but haven't found any. Is there a best way to find one that isn't obvious?

I do have the ribbed PCV hose.

A year ago I changed the spark plugs and replaced all the gaskets involved with getting to the plugs. Would that include all 12 of the ones you mention?

I can remove the MAF and look for obvious dirt, but other than that, how do I tell if the MAF is bad?

Bob

 

I'm guessing bank 1 is upstream and bank 2 is downstream? I also have Bank 2 sensor 2 that needs to be replaced as well.

*sigh.. So many familiar dilemmas.

 

No the banks refer to the two different arms of the "V", 3 cylinders in each bank. Each bank has an upstream sensor on the exhaust manifold, and a downstream sensor on the cat converter. Four O2 sensors total.

 

Bank 1 is next to the bulkhead/firewall, Bank 2 next to the radiator.

 

Bob,

Taking out the MAF is easy. However, you cannot tell if it is dirty by manually inspecting it. You should pick up some CRC MAF cleaner and spray the sensor clean. Be careful not to touch it, since the sensor is very delicate and may break.

I would also, clean the throttle body as well.

I've attached pictures of the MAF sensor and the 6 upper gaskets and 6 lower gaskets - below the fuel rail. Just to make sure we are on the same page for the 12 gaskets.

 

Jeeves12,

My notes say that I replaced the 6 gaskets "on the intakemanifold" in May 2011. Those should be the 6 in your picture. I'm wondering where the other 6 are that youmentioned.

Thanks for your help. I really appreciate it.

Bob

I'll get some CRC MAF cleaner.

I visually looked carefully for a vacuum leak but didn't find anythingsuspicious. What's the best way to eliminate a possible vacuum leak?

 

The other 6 gaskets are under the lower manifold. See this thread for pictures:

https://www.jaguarforums.com/forum/x...ted-how-62847/