I was having misfire issues with individual cylinders on my 04 XJ8 and after paying my local repair shop to replace the coils one at a time, I decided to just go ahead and replace all the plugs and coils myself. There were a few issues with coil screws stripping and plug boots ripping and getting stuck on the plugs, but I finally got it done. Now it runs great but every now and then, upon starting, it runs rough and then runs fine as soon as I start driving. Then the engine light goes on and I get a reading of cylinders 1,3, and 5 misfire. I can clear the codes, and it runs fine until the next occurrence. I ran gas treatment through the gas tank to no avail. Any suggestions as to what else it could be?

 

Perhaps try the correct forum. This is the X Type (X400) forum.

 

I'm new to this. What forum should I be using?

 

The X350 if your vehicle is a MY2004.

What other DTCs are showing up besides P0301, P0303, and P0305? Since all the misfires are occurring on Bank 1, are you also seeing P0171?

 

https://www.jaguarforums.com/forum/xj-xj8-xjr-x308-27/

 

Thanks. I found the right forum and copied the post to it. And to answer your question, I did not get that code. I only got the random misfire and the multiple misfires codes in addition to the 1,3, and 5 misfire codes.