Hey Folks,

Recently, I had the 2 codes above thrown on the Jag and the car had a lumpy idle.
On first site, it would make sense that the cause was a faulty ignition coil as mine are getting on in age.
Swapped it out with no change
So then I moved on to the spark plug in the hopes that I just had one suffering a premature death but nope - not that either

In my case, it turned out to be a failing fuel injector.
I had bought a rebuilt set last year to replace all of my originals due to the bodies cracking and I guess I had a near-death unit in the lot.
Contacted the seller who was a ebay seller in California and reported the problem.
They never asked for the bad one back and instead of getting a free replacement - they sent 2! Good on them
So if you are throwing these two codes, just know that they do not necessarily add up to what you think (a misfire due to spark delivery)
Swapping out fuel injectors is not rocket science either. From the moment I started until I finished replacing the bad one, it took no more than 40 minutes of work.

Hope this helps someone else

Bernie

 

Hi Bernie,

Thanks for your successful diagnostic report! I have edited the title of your thread to indicate that you found a solution to the issue.

For future reference, here are the definition and published possible causes of the P0300-P0308 misfire codes:





Cheers,

Don

 

Awesome Don and thanks.
Search engine optimizing a post is my pet peeve as I have wasted countless hours searching dead ends about issues I have faced.
If the changes you made make this, and other posts I have made more visible, it makes me happy and undoubtedly will help other owners