I'll start by saying I will get the codes again if necessary, but hopefully someone can solve this issue tonight before I leave my home again.

Months ago I took my 05 XJ8L (85,000 miles) to Auto Zone to have it checked. There were about 6 codes including lean banks, o2 sensor fail, maybe vacuum issues. It's been a while and I lost my printout.

I have taken it to the dealer for regular maintenance since, so I had them "fix" the problem. They also checked the codes, I didn't ask what came up as they said they fixed it by resealing the air box that was installed improperly.

I drove it home about 40 miles with no problem. The next day after only a couple miles of driving it appeared again, check engine and limited performance (LP).

The check engine light stays on until you plug in again but LP is very sporadic. It seemed to come on after some type of change. Stopping for fuel on long drives, or if it was on before stopping, going off after stopping, coming to a stop after highway driving, etc.

I read somewhere about someone having similar issues and followed their advice. This is what I tried, in order, maybe a week or so apart. New fuel cap, fuel filter, mechanic sprayed cleaner on sensor in air plenum, and injector cleaner in 2 tanks of fuel.

None of these solved the problem but the injector cleaner seemed to help as the car did run smoother and the LP message showed up less. Although it has a huge hesitation when accelerating or even revving in neutral, way before the 3000 rpm rev limiter.

The car is very sound and I'm sure (or hope) it is an easy fix. I'm thinking I should lean towards an air leak since that's what the dealer tried to fix. Do any of you guys have a suggestion?

Please respond to this if you have had a similar problem or know someone that has.

My wife drives this car semi regularly and it is not safe to be driving and have it cut off at 3000 rpm's.

Thanks in advance for your help! Kevin

 

Kevin, firstly sorry to hear about your issues....

Your original post, long unbroken lines of text are hard to read, meaning many members instantly switch off.
I've added line breaks for you in this instance.

Re your issues, I can't offer much specialist advice, except as I was reading, my initial thoughts were "perhaps" 02 sensor related.

You say a code read confirmed this?
Yet the 02 sensors were never checked / replaced?

Hesitation / surging / increased fuel usage can all be 02 sensor related, either failing or failed.
Its certainly worthwhile at least looking at this aspect further on an 05 with 85k miles.

I'm not saying rush out and replace, I'm suggesting they should be checked more thoroughly and a possible culprit.

I'm sure some of the real tech savvy diy'ers will be along to help shortly.

Good luck

 

Maybe move to the right forum where the right folks can see it...

 

Kevin,

I'm sorry to hear that you continue to have problems with your '05 XJ8L. The short answer is that one or more Diagnostic Trouble Codes (DTCs) or fault codes have almost certainly been logged in one or more of the electronic control modules in your car, and they need to be scanned in order to understand what system or systems are involved and what corrective measures need to be taken.

The scanners used by AutoZone and other parts stores can read the generic OBDII codes, which reflect emissions-related issues, but there are many, many other codes that relate to other systems and are proprietary to Jaguar. In order to read those codes, you will need to go back to the dealer or to an independent Jag specialist with the appropriate dealer-level scanning equipment. Until you know what codes have been triggered, you can only guess at what the problem or problems may be.

If you are willing to invest some time in educating yourself, you can study the X350 Workshop Manual, which can be downloaded from this forum in six sections:

http://www.mediafire.com/download/md...f+contents.pdf
http://www.mediafire.com/download/aa...nformation.pdf
http://www.mediafire.com/download/n3...2.+Chassis.pdf
http://www.mediafire.com/download/9b...Powertrain.pdf
http://www.mediafire.com/download/0i...Electrical.pdf
http://www.mediafire.com/download/4j...+and+Paint.pdf

I would suggest you begin in the Powertrain section of the manual. You can use the Adobe Acrobat Reader search function by holding the Ctrl or Cmd key down and pressing the letter "F". In the search window that appears, type Restricted Performance and then click the NEXT button to toggle through the occurrences of that term to see the many, many malfunctions that can lead to Restricted Performance.

I'm sorry I can't be more specific until we know the code or codes that have been triggered.

Please keep us informed.

Cheers,

Don

 

One other item is the battery. If it's more than 3-4 years old, I suggest replacing it now. Your multiple symptoms may not be battery related, but it's very good insurance anyway..

 

I have a 2004 XJ8 with 200,000 miles.
A couple years back, during cold weather ONLY, I would get a loud ticking noise from the left front fender after coming off a highway or when idling. This is where the Fuel Vapor Purge Valve is located. The purge valve would make a racket... I got in and insulated it. Lately I had the same symptoms as you... check engine light is on. Lean in both banks, Evap. Emissions leak. P0455, I think.

Car goes into limited performance periodically. Actually when you start to closely look at the limp mode it only comes on after coming off highway driving, or around town driving. Same as the Purge Valve noise in the winter, only now in the summer too, but no noise.

So... I did a smoke test. Guess what has failed, yep, the purge valve. I got one on Ebay this week and will replace it this weekend and give you a report. I am betting that will fix my P0171, P0174, P0455

Yours sounds the same as mine.... You will need to do a smoke test....

Tom