my 2000 vandem plas xj-8 has oil on plug threads and once my engine heats after 20 miles of pristine driving. I get restricted performance limp mode.I had the vehicle computer read at local advanced motor parts co. they gave me the following codes po 300 misfire.po 302cylinder.pl 313 lean.and po 352 coil B. I need this interpreted as I know only general engine mechanics mostly maintenance.My fear is oil on plug threads and the possibility of compression loss leading to expensive ring replacement or cylinder bore.I am hoping for oil plugs or something less expensive ugh!!! Please help me gus or anyone equally knowledged.I love my Jag.

 

the 2000 xj8 is actually the X308, all your future posts should be added over there, ok?

Now, the 2000 MY has the 4.0 which is notorious for leaking valve cover gaskets, oil drips down and right into the spark plug wells, that's where your oil is coming from most likely. The replacement of those gaskets are pretty straightforward, and also make sure the existing valve cover isn't cracked or broken from being overtightened, they are sensitive to that.

Now, after cleaning that mess up, if you're still having a misfire, you'll need to figure out if its the coil or spark plug. Easy to diagnose by swapping coils around and seeing where if the Pcode follows that particular cylinder/coil.

Here is a thread with the EXACT same symptoms, you should be able to solve your problem armed with this info. BTW, yes, same engine as your XJ.

 

moved to x308

 

Hi
Here are 2 forum threads on valve covers - 1st one gives valve covers gasket kit info & pricing, 2nd one gives instructions on how to replace them:

https://www.jaguarforums.com/forum/x...eed-how-81632/

https://www.jaguarforums.com/forum/x...xtracts-66696/

Jim Lombardi

 

one note, if you are pulling the valve covers take a look at your tensioners while you are already in there. Also take a flash light and look along the timing chains to see if you have the new chain slipper guides or old ones (Orange)