Car started alternating between running rough and just fine. I thought it was fuel as I recently topped up tank with high octane fuel.
I added fuel treatment to improve things but rough running turned into restricted performance. However, will occasionally clear and run smoothly for a short while before going back into restricted performance mode.
Here are the error codes p0303, p0305, p0308, p1316, p0352, p0353, p0355, p0358, p1000, p1368
I put new fuel filter on; checked plugs on both banks to make sure there was no moisture or oil; cleaned contacts to all coils; cleaned sensor connections on top of valve covers.
Battery is in excellent shape and car is on C-tech battery maintainer when not being driven(haven’t been able to drive it for two months).
Any suggestions for next steps! Thanks

 

P1368 definition should give you some pointers:



The motor will run rough as the ECM will shut off the injectors to the affected cylinders in response to the P035x codes.

Check the wiring around the engine loom, or it's possible that a bad coil can take out the group. Try unplugging one at a time in the group to see if that makes any difference.

 

Hi Ken,
I stumbled upon this reply in an old thread of giandanielxk8's so I've copied it back in here:

I do sympathise - intermittent faults can be a PITA to track down Driving it around with 7 cylinders isn't really an option, so it's a case of catching it while it's misbehaving, Frustrating.

 

This morning I drove it about 15 miles. Ran very rough with restricted performance light on dash during start up and idle. Got a couple miles and all smooth….several more miles and restricted performance light disappeared. Stopped to top off the tank with best high test fuel in our area. Started up and rough idle returned but as soon as I pulled away at modest speed the rough engine disappeared and drive was beautiful. No rough running or return of restricted performance light. Is it possible that the entire issue was caused by bad fuel? We will see. Planning to get it back on the road no later than tomorrow. Will send report. Zray’s contention that the car needs to be driven is looking likely true for this one!?!

 

The best way to keep these cars healthy is indeed driving them in a spirited fashion on a regular basis. My wife prefers her SUV and very rarely drives her 2006 XK8, so I take it out at least once a week for a 25-mile jaunt. Works for me....

 

Update:
Having a streak of bad weather and family visits have kept me from working on the xk8 issues. Have driven it several times and continues to run rough and then engine smooths out. Occurs in no particular order. I do have fewer codes. Now only: P0353, 0355 & 0358 with also P1000 & P 1368. I am searching around the engine compartment for loose or bad grounds as well as anything suspicious with the engine wiring bundle.
Several posts with similar symptoms have been found to be ecu module issues. I want to eliminate everything else before moving to that.
l appreciate any suggestions and thank you for taking the time to lend me advice!

 

I pulled and opened the ECM. I have at least one orange colored capacitor which has apparently failed and spilled fluid. I plan to send the unit to a diagnostic facililty. I am open to suggestions. I see ecudoctors.com in Florida as a possible provider. Any suggestions???
Thanks,

 

There's also Module Repair Pro in Van Nuys, CA or, possibly, ASI. Best to call to check if they can oblige, I guess.

Can you post a pic of this please?

 

See capacitor where marked with circle
not sure the photo is dense enough to show it

 

Ecu doctors in Florida and Automotive Scientific Inc don’t do diagnostic testing or repair of our ECM. Awaiting response from Autoecu.com
if anyone has recent experience with this service I would be grateful for the referral. Thanks

 

Thanks for the pic. There is some detritus between R823 and the resistor R?6 marked '512' above it


but that should clean off with a little isopropyl or distilled water on a Q-tip.

No electrolytic caps there that I can see, but there will be more components on the other side of the pcb.

Beware that the repairers can be tetchy about taking in modules that have been opened. Isn't Autoecu.com ASI?

 

UPDATE:
I sent ECM to GOecm in Texas. They reported back that their testing revealed no issues and that the board tested good. I reinstalled it and am still getting same symptoms. Not sure what next step as I was counting on the board being my issue. I will double check fuel pressure and maybe move coils around?? My diagnostic abilities have pretty much run out. Open to ideas. I don’t know/haven’t found any Jaguar techs near. Thanks for any ideas.

 

Could the MAF cause these symptoms?

 

Are you still seeing P1368?

 

The 355,357 and 358 codes all refer to the coils of cylinders 5,7, and 8, respectively. They're all on bank 2, so this narrows it down a bit, I think. IMO you should move one, perhaps #5, to the opposite bank, in this case cylinder 1, and put cylinder 1's coil on 5. Then drive it around and see if the error returns, and if the error follows the coil. If it does, replace that coil. If it does not, put things back where they were and do cylinder 7, and so forth. This would at least help to determine if it was a bad coil(s) causing it, or something deeper in the wiring. My theory, and it's worth every penny you're paying for it, is that one of the coils is causing the issue with all three.

 

Michael, Yes, sorry for the long delay but have been away and not able to work on car.....
my car has an aftermarket air filter (K&N) fitted by previous owner. I have decided to purchase a stock filter box and associated fittings as I am thinking that the K&N is potentially oiling the MAF and is also introducing air drawn from within the under hood space heated by the engine/radiator as opposed to air pulled from within the right front fender well. I am awaiting delivery of these components in the hope that this will make a difference in symptoms.
I will report back s soon as I receive and install. Car still runs mostly rough with restricted performance displayed ....although will occasionally smooth out for a bit.

 

Have about same issues. But 2 coils are not firing on each side of my 2000XK8? Changed all coils and plugs, new fuel injectors, and just got back my rebuilt ECU/ECM from (Foreign auto computer) Texas. 1-800-241-6689. Sill same codes and same coils are not firing???? Injectors are working fine. I am at a loss? Anyone?

 

I don't think the aftermarket filter arrangement is the cause of your issue, but I applaud your decision to junk it in favour of the stock filter.

The car is complaining that it can't 'see' the spark confirmation signals - P035x for individual cylinders, P1368 for the group. It could be a coil module, wiring or ECM issue.

If you're confident that there's not a problem with the engine wiring loom, then it could be a faulty coil module affecting the others in the group. Either:

• If you have a spare coil module to hand, then you could try a substitution of each coil in the affected group:- note that a 'group' is two cylinders from each bank ( in this case 1B,2A,3A,4B) not the four from one bank.
• If not, then try what Y2KJag suggests by swopping each coil module from one bank across with the one opposite, one step at a time, and check if the DTC changes to P1367.

I'm afraid both are tedious, but they are $0

 

I exchanged the coil modules from cylinder 1 and cylinder 5. I ran the engine- just idle. I did not drive it. It idles no differently that it did before the switch of coil modules. Not smooth/rough like cylinder not firing. I checked the codes to see what difference if any were shown on my scanner.
Scanner codes before the switch were: P0300, P0305, P0308, P1314, P1316, P0352, P0353, P0355, P0358, P1000, P1368
Scanner codes after module switch: P0353, P0355, P0358, P1000
There is no "DTC" change to P1367. Could it be that this is because I didn't drive the car??
Is this a change sufficiently significant/specific that it is diagnostic?? I can't figure this out.
Do I have anything diagnostic of a bad coil module?
Not sure what I should do next as I still have about the same operating- bad running engine.
I have also discovered a high pitched whine sound that comes on with the ignition. This is NOT normal and I can't figure out where it is coming from Seems loudest in the throttle body area.
Any thoughts/suggestions appreciated.

 

Ken,
On reflection, I've been over-complicating things. The swop of the modules across banks won't 'fix' the problem, but it could help narrow down a faulty module.

The simplest check I can suggest is to disconnect the modules for B1, A2, A3, and B4 one at a time in turn, then running the motor for a few seconds. If it is a coil module issue, then any returning codes should just relate to the cylinder with the unplugged module.

No need to drive the car:- just running the motor for about 10 seconds after each change will be enough to throw P035x codes. Try that and see if anything changes.

Quick Q:- does it run smoothly for a brief period (seconds) after startup?

My car produces a 'buzz' from the throttle body motor with the ignition switched on. It's a slightly different arrangement than yours, but it runs faultlessly so I've always assumed it was normal.