The mother in laws Jag developed a bad miss the other day with a CEL. Going through the codes it looks like a miss fire. Since these were the original plugs I started with them. To my surprise there was a considerable amount of oil in the spark plug wells. Is this from a leaky valve cover gasket?

Thanks, in advance!

 

Probably. The O-Ring seals under the center of the Valve Cover need to be replaced.

The gasket set FEL-PRO Part # VS50724R or
VICTOR REINZ Part # VS50397 includes all necessary seals.

 

Is that the right Fel-Pro number? Looks like Ford/Lincon 3.9l.

 

Yes, AJ27 (1999-2002) XK8s use the same Gaskets. The Lincoln LS V8 Engine is a version of the Jaguar Unit.

 

Misfires are a common sign of coil failure as well. What codes did you get? If you post the codes or know which cylinders are bad, swap the coil with a good cylinder and see if the misfire follows the coil from the bad cylinder(s). And yes, as Paul said, time for new gaskets.

 

One side done and new battery installed. Now I'm getting an ABS failure as well as :

P0357 - Ignition Coil G Primary / Secondary Circuit
P1000 - ODB System not ready (if I remember correctly)
P1649 - FCCP Monitoring Flash Memory Malfunction

I was getting a miss in cylinder 6 and swapped coils with cylinder 7. Initially it ran fine but shortly developed a miss.

Sounds like I need at least one new coil. Are the Denso coils significantly better than what I can get at the local parts store?

 

Bump...