Restricted performance

[Rich1973]

I have had my XJR since the end of March and not had one iota of trouble with it until last saturday when me and the girlfriend were due to go on holiday for a week. I packed all the bags, jumped in, fired it up and it settled to a rough idle with the amber light on and restricted performance written in the message centre. I had a look around the engine bay best as I could and nothing was obviously wrong.
In the end i decided to drive it gently as I wasn't going to have my holiday plans ruined. The engine was also quite rough during gentle acceleration sending a vibration through the whole car.
After about 7 or 8 miles, we pulled up to an island and the tickover was very smooth again, and shortly after, the warning disappeard and the car was faultless throughout the remaining 140 miles.
All this week, the warning has come and gone intermittantly, and seems to go out after 7 or 8 miles each time presumably when everything has thoroughly warmed up.
To me it feels like it is not firing on all cylinders and I wonder if one of the coils has developed an intermittant fault.
I have read mention on the forum before of a couple of good independant garages in the Nottingham / Derby area if anybody could point me in the right direction please but in the meantime i was wondering if anybody could give me any idea as to what the problem is likely to be?

Many thanks

Richard

[charliebrown]

Possibly an ignition coil going down Richard. If it does turn out to be that, let me know and I'll pop you one in the post. Got a few kicking around. Codes will be P030* the * will indicate the cylinder number 1-8.

[xjr Jack]

Hopefully it is a simple as a coil pack.

In my case, with similar symptoms it was a tensioner gave way.

viewtopic.php?f=35&t=25595

[Rich1973]

I have asked my mechanic to hook the car up to an OBD2 this afternoon which he has done and as Charlie says, it has come up with P0307 "cylinder no.7 misfire".
We have had a look at his technical manuals on the computer, and the cylinder numbers arn't shown on a diagram for the X308.
For a 4.2 X350, no.7 is the most rearward offside cylinder (nearest the steering wheel). I am assuming it will be the same for my engine, but could someone confirm this for me please?

Many thanks

Richard.

PS Sorry to hear about yours Jack, cannot have been a good thing.....

[voodooman]

They number from front to back.

The right side (when sitting in the car) is 1-4, the left side is 5-8 in an X308

Regards

peter