I have a 00 XJ8. Restricted performance came on, so we started the cheap route and replaced the spark plugs. Kept happening. So we replaced coil 6 and 2 (we switched them to see if the same code would come on) which it did, so we can rule out a bad coil. What else could be causing this because trying to figure it out is expensive. Also, cloxk works but is really slow. Like it will lag behind.

 

A weak battery can cause many problems, so have it load tested. It would be appreciated if you would list the actual codes.

 

Hi Brianna Renee,

+1 on having your battery load tested and having the fault code(s) scanned and posting the full codes here so you can receive the most accurate and thorough assistance. The codes will be in the form of P0306, etc.

Cheers,

Don