Jaguar issues related to p0300

Thank you for responding to my question. After many replacements of different parts trying to narrow the problem down, it came down to finally taking the drivers side spark plug coils off(passenger side consist of the dreaded manifold removal). After removing the coils, I found the spark plug wells contained WATER!???? Was very shocked. Anyways, dried the wells and coils completely. Replaced everything and the car ran somewhat normal. This is completely surprising to me. So now I guess I have to have someone remove the manifold and do the same thing to that side. Not sure how the head gasket got cracked (seems like that's the problem). No warnings. Thanks again.

Water could be from a bad weather strip where the hood meets the firewall or from someone washing the engine.

If that was the case?? How would the water get down into the spark plug wells?? Those coils are screwed down airtight. But.... I wish it were that simple. It would probably save me my car. If it's actually the head...done deal for me. Unfortunately. Thank you for the information though. Much appreciated!

Apparently not so air tight. My Fords (yours is a Ford too!) have had this problem. If you remove the coils use a dielectric grease on the coil boot rubber surfaces to help keep moisture out. Obviously avoid deep puddles if you can.

A leaking head gasket would not leak water into the plug wells.

Thanks so much people. These positive replies mean alot and are very helpful. I appreciate every comment. I was pretty much convinced that the only way leakage could get into the the wells was through the head gasket. Kind of encouraging to hear my car might make it. Lol. I laugh in jest because it's my favorite car and if it's the head gasket, I'd have to let it go. Thanks again for all the informational help.