A number of members have posted remarks on the supercharged cars with rough idle and/or misfire. I have been to the dealer many times for this problem, and now have a case open with Jaguar engineers.
Unfortunately, they do not know what is causing the issue and they do to expect a fix anytime soon -
The problem has been there since day 1 and we were reassured it would be fixed with some fuel injector cleaner. After two treatments, the recommendation was for a treatment to clean carbon deposits above the valves. Then there was a software update. Last time, I was told that nothing was wrong with the car, it was normal, and other supercharged cars were doing the same.
After some discussion, the service manager agreed that they had treated the issue as a problem on multiple prior occasions and basically don't know what is going on. I asked for a case to be opened with Jaguar.
They collected data from the car. I was told that the lead engineer for Jaguar North America was aware of the problem, in fact, the car he was driving had the same issue.
They think it can be corrected they a software update, but no fix is expected anytime soon. The more customers that report the problem will help with a quicker fix. They also mentioned that some cars are worse than others, but all SC cars seem to exhibit the problem. The cars that are worse, also have excessive carbon soot at the tailpipes. My car will have thick black soot on the tailpipes within a day after washing it clean.
We love everything else about the car, but this is a huge issue for my wife. It is her DD. She would have never accepted delivery or bought this car if she knew the issue would not be fixed. Until now, we have tried all of the available recommendations, but are now at an impasse.
I offer this experience for those who own or are considering a supercharged jag.

 

I am no expert. But could it be that the Jag's SC V8 engines need stiffer valve springs, and perhaps a different cam with slightly less aggressive lobes?

 

I had very mild vibration on and off but lately disappeared as I kept the car exclusively on Exxon/Shell diet. What kind of gas do you use?

Top Tier Gasoline

 

https://www.jaguarforums.com/forum/x...s-today-65247/

https://www.jaguarforums.com/forum/x...e-again-43008/

https://www.jaguarforums.com/forum/x...r-71127/page5/

Evidence points to a bad batch of 5.0 S/C’s (cylinder heads?)- not just rough idle, but actual misfiring. Regrettably, this was enough to put me off pulling the trigger on a 2012 XF Supercharged. I love the 5.0, which is surprisingly strong off the line- feels E39 M5 quick to me- but at highway speeds there is an obvious gap in pull vs. the S/C’s.

There are posts indicating that some individuals have been able to get new engine or even new vehicle replacements from Jaguar NA, but I don’t imagine it the easiest or most straightforward fight to pursue. Hopefully Jaguar can come up with a reasonable fix- their current lineup is the best in years, and these lingering reliability concerns (real and perceived) are stunting what should have been a robust brand rebirth.

Best of luck!

 

Thanks for the input. The roughness is very random, no specific pattern. It is important to distinguish between variations of the idle rpm (I would consider this normal) and a profound jerk felt throughout the car, like a misfire. Since it is so random, I doubt this is related to valve spring stiffness or cam profile, but certainly a possibility.

Jaguar seems to believe it is an issue to be corrected thru a software update to the ECU. But, if it were that simple, why wouldn't we have a fix by now?

 

I always use top tier gasoline without any ethanol. The same gas is used in my other vehicles and they have no problems whatsoever.

Even so, Jaguar sells these cars in the North American market, so they should be designed to run on readily available fuel in those markets.

There is nothing in the owners manual, marketing, or disclosure when I purchased the car that says you have to use a specific brand of fuel. Jaguar only specifies using premium unleaded fuel. Regular unleaded will not cause engine misfires at idle, but may only cause knocking when under load. The ECU should adapt to fuel octane by adjusting ignition timing. The power may be reduced, but there should be no misfire.

So, I don't buy into the "what kind of fuel do you use" philosophy. Can you imagine the hit on sales if Jaguar were to require you to use a specific brand of fuel in order to prevent engine roughness or misfires? They wouldn't be able to sell many vehicles.

 

Thanks for the input!
I have read a few things about cylinder heads too, but I can't find any specific evidence, let alone regarding which VIN's might be affected.

Can you point me to specific credible info on this subject?

A Jaguar case number or copy of service ticket would be extremely helpful.

 

Sorry, I don’t know any details beyond what’s been posted on the forums. Assuming other members here have been upfront about their experiences, e.g. Jaguar offering an outright vehicle replacement or a new engine swap, the misfiring issue looks to be a real and serious one if you happen to luck upon a bad 5.0 S/C:

https://www.jaguarforums.com/forum/x...r-63871/page3/

There is also a 2010 XF Supercharged owner on another forum who had his vehicle successfully lemon-lawed for the engine misfiring (along with a litany of other problems). It wouldn’t surprise me if Jaguar is less than forthcoming with specifics- you might want to try contacting forum members RJC or superflysocal directly.

If it was a matter of software, I don’t see why there wouldn’t be a definitive patch available by now- the 5.0 S/C has been in production since MY 2010. Like I said, I imagine it would be an uphill battle with Jaguar NA, enough so that I was too hesitant to chance it myself with a supercharged variant. It’s really a shame, as issues aside, the 5.0 S/C puts out undeniably seductive levels of power.

 

While I understand everyone's frustration, please believe this business is frustrating for us as well. I just want to add a couple things for all to keep in the back of their mind.

Fuel quality and chemical property is a moving target, WORLDWIDE. You can't just say, gas is gas. Gasoline is a regional product. Meaning it is blended/refined to meet regional need based mostly on climate. Please believe that constitutes a challenge for anyone's engine systems to fully/reliably compensate under all conditions.

Now, here in the states especially, don't forget everyone's friend, the EPA. Some ask, "Why don't they have a fix by now?" The answer usually lies at the feet of the EPA and the "certification" they require for EVERYTHING automotive. The mfg. can't do anything, make ANY change to ANYTHING that has ANY perceived impact on exhaust emissions, [good or bad] without submitting to the EPA for approval. The EPA has to protect us, remember!

As you can imagine, any change that might have a bearing on possible misfire correction, also has to go through the EPA red tape for certification. If there is something there they don't like, whether directly related to what they are trying to correct or not, they can send the mfg. back to the drawing board to start over. It can be a viscous cycle.

This is the kind of thing most folks don't think about. I just wanted to provide a little perspective. Believe me, they would love to be able to nail down an issue, figure out the correction and put it out there, pronto. But it's just not that easy.

No excuses, just information........

 

Thanks for the response.
I think everyone realizes that changes must go thru the EPA for emissions, etc.
But my point, how did this ever make it to market and in my driveway before this was fixed? Is gas a moving target? Not really. There are summer and winter blends and regional differences, but the EPA regulates all of that too.
Is it hard for engine manufacturers to develop engine systems to handle variations in fuel? It may be hard, but is definitely doable. Seems like everyone else has it figured out. Every Lexus, BMW, GMC, Porsche, Toyota, Acura, Maserati I have ever owned had it figured out and they run on the same gasoline from the same gas stations. It just appears that Jaguar hasn't quite figured it out yet.
The issue was noted on the test drive and mentioned to the dealer. We were reassured it was something easily corrected as it was just from the car sitting on the lot for a while. Unfortunately, that hasn't been the case.
My dealer has contacted Jaguar NA and has not heard anything back. He suggested I contact Jaguar NA to see if I could get things moving. I haven't heard back from them yet, either. Seems like a sad, sad state of affairs when a dealer can't even get a response from their manufacturer.
No excuses.

 

Sorry about your problem and what seems like lukewarm responses.
It's your fault though - making the poor thing share a garage with a BMW.
I'm not surprised she gets the shakes.

 

Sorry to hear that you haven’t been getting much traction to date. I'm not sure when you or your dealer initiated contact, but hopefully persistence will pay off in the long term. In the short term, if they've been nonresponsive this week, keep in mind that Jaguar NA's headquarters in Mahwah, NJ may be without power and recovering from flooding/storm damage for at least a few more days.

 

teachdocs,

This is a little off topic, but how do you like your Maserati? I was thinking about getting one, is it worth it or too much pain to service it? Thanks.

 

Did you ever get anywhere? interestingly I have a 3.0 Petrol that has started to show a rough idle and the only thing I can find is a fault around the ignition timing, its jumping around below 1500RPM. Yet to find the cause, but its driving me mad.

 

FYI my 4.2 XK also has soot on the tailpipe after just a couple hours of driving. When you say there is a misfire, how do you know? Check engine light?

 

Bit weird to put a 3.0 issue into this thread!!

Probably an air leak. Best start a new thread and put car details in as well.

 

Awhile back on my 2013 SuperSport I had an exhaust camshaft timing adjuster fail resulting in a slightly rougher idle and a little less performance, it took a couple of weeks and then finally got an error check engine light and the dealer diagnosed it and replaced it quickly. Seems that unless an error occurs at least twice in a relatively short time period an error light will not be triggered. Once the light came on the tech was able to read the issue and stated it had started when I first had noticed the performance and vibration issue.

 

Interesting to see the various problems that individuals continue to have on these cars.
My OP had to do with a NEW car which had a rough idle/misfire like condition at time of initial purchase. Various steps were taken by dealer and Jag NA to fix the problem, only to be later told that there was no problem and it was operating according to design.
I wish to reiterate my frustration with Jag NA for simply writing it off and not addressing the problem. Having one bad car is one thing, but when the manufacturer won't stand behind their product, that's another.
I learned my lesson with Jag and will unlikely ever buy another.
They are beautiful and powerful cars when working. When they don't, you are SOOL.

 

Dear JagV8, its not really a Bit weird to put a 3.0 issue into this thread, my reasoning, these jags are technical from the same house, the computers, and general technology is from the same stable, if your write software you will know that you never start from scratch, so whats in one car will in some way be in another. So its possible that faults could be common across the styles. That was all I was thinking.

As for air leak good idea, would that cause the Ignition timing to jump around on idle?

Regards Geoff.

 

Still wondering what the symptoms of a misfire are if jaguar can claim it is normal...