I'm having this same problem but the car runs fantastic..

 

By the way, I just spent $450 to replace all plugs but the light came back.

 

javaluva, odds are you got water inside the wells on the affected side. So, you will need to access the plug wells and make sure that they are dry. Pressure washing the engine bay is a bad idea on just about every new car out there these days. You are normally fine as long as you don't spray the top of the engine.

If the plug wells are dry and you are still having this issue, then you more than likely affected the ground wire for the coils. Follow the wire run to the ground point and remove it, make sure the mating surfaces are clean and then put it back down. After that, you are going to need to do some voltage measurements to determine what is wrong.

 

Thanks Thermo, in your opinion - with my case the plugs were changed so water would have been noticed. Where would be the best place to start if water is ruled out? I can tell you, I smell a "burnt" smell at times coming through the AC vents. Maybe that's just a result of the misfire but I never notice a misfire regarding enginer performance/sounds.

 

rtmolder, from the looks of things, what you are going to want to to do is to get access to cylinders 1, 3, and 5 and then do a hand over hand of the wiring, specifically looking at the yellow wire with a green stripe on it. This wire is the common wire between those 3 coils. If you see anywhere that the wire makes a dramatic turn (indicating that the copper is broken inside) or the wire has been cut, a repair to the wiring will need to be done. The yellow/green wire feeds back to the ECM. If there was to be another problem spot, it would be with the black wire coming off of each coil (goes to a common ground point) or a green wire (has numerous colored stripes depending on which cylinder we are talking about). The green wire should have 12 VDC on it when the ignition is turned on.

Hope this helps. If the wiring looks good, then taking the car to an electrical specialist will be needed as the diagnostic tools to go beyond this are beyond what the average person has in the garage. I'm not sure if you would want to work on getting a new part of a wiring harness to try and eliminate the wiring as the problem is most likely either something in the wiring or a problem with the ECM.

 

Forgive me, but is this the 3.0 engine?

 

Thanks Thermo! ... and yes Rick, it is the 3.0.

-Rick Molder

 

How are they numbered.. which cylinder is which?? I'm having misfire on the exact same cylinders

 

1,3 and 5 are at the rear of the engine close to firewall and 2,4 and 6 are at the front near the radiator.

 

Just what I figured. Which means to change the plugs I'll have to pull the intake and replace the upper intake gaskets while I'm at it.

 

I have reused the gaskets on low mileage X-types but it is best to replace them. If you don't yet have it download the tech manual for the X-Type. If you go to JagRepair.com - Jaguar Repair Information Resource and go about 2/3 of the way down, in the x-type section, you can download the sections that are a complete tech manual.
Make sure to follow the torque value and sequence when reinstalling the intake. Make sure that the engine has sat overnight, removing the intake bolts on a hot or warm engine can strip the brass inserts out of the lower intake manifold.