my 2006 XJR with 151,000 miles developed rough running with a miss. Codes were P0307 and P0316 accompanied by intermittent restricted performance. Restricted performance would clear itself for a minute or so, followed by return. Although P0307 is listed as cylinder 7 misfire, I was not able to find a listing for P0316. Anyone know the definition?

After reading a few other P0307 code posts, I realized that I must have an ignition coil going bad. After sitting for 8 Hours, I still had the miss, rough running and restricted performance.

I looked at the online JEPC and determined that the coils are AJ810445. Spark plugs are AJ84575 but have apparently superseded by C2A1535. Not knowing the age of either the plugs or coils, I ordered eight of each, Spectra Premium coils C777 and NGK5464 Iridium plugs from Rock Auto. I think the gap is supposed to be .040"?

I removed the top engine cover and tried to remove the coil covers on the valve covers, but can't figure out how the covers are secured. On my last car (a 99 X308 with 4.0 Liter engine) the coil covers bolt on with six bolts. The covers on the 4.2 liter XJR supercharged engine seem to be snap in place, perhaps with plastic tabs, but I can't get the covers to come loose.

The shop manual was not much help saying "remove the coil cover" but not describing how to do so.

Can anyone describe how to get the coil covers off without breaking the cover or attachment, please?

 

P0316 is engine misfire during first 1000 RPM of startup. Coil covers do just snap on or off, this link will give you an idea of their construction.
http://www.ebay.com/itm/Jaguar-XJ8-V...7/112420623426

 

I used a pry bar to pop the covers loose after looking at the ebay link from woox4.

Getting access to the left rear coil looks like it will be tough. I think I saw a post about removing the cover for the brake master cylinder to get room. I will have to search.

 

Here are photos

 

On my 2005 XJR there is such a panel. That is how I gained much easier access
to that driver side rear coil/spark plug.

Getting that panel off however is a little tough.

The black tubing goes thru the panel on my car.

 

Maybe P1316 not P0316?

 

mikebaker3 when were the plugs/coilpacks last changed?

 

Originally Posted by mikebaker3 View Post
I used a pry bar to pop the covers loose after looking at the ebay link from woox4.

Getting access to the left rear coil looks like it will be tough. I think I saw a post about removing the cover for the brake master cylinder to get room. I will have to search.

Appears that L-R coil will be an issue, but it is not all that difficult. A little turning, & it can be pulled up and out without much resistance at all. Plug is then removed with same extension, flex joint, & socket as the rest. A little never seize on the threads after checking the gap, reassemble, test drive.

 

Car had about 137,000 miles on it when purchased July 2016. No way to tell how old the plugs or the coils are which is why I am going to change both for all eight.

 

Good idea; The plugs for sure, while you have them in your hand the coils are too, if the funds are available.