Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
Hi, my name is ***** ***** these codes, you most likely have bad gaskets on the #1 bank intake manifold, it is showing a missfire on all three cylinders on that side, have you checked for a vacuum leak on the #1 intake manifold bank?
hw did yu check it? did you use a smoke machine?
when there is a missfire i one or more cylinders, it can cause the cat converter to plug up, thus the P0420, but before the cat is replaced, you need to find the cause of the missfires, if all 3 of the cylinders are missfiring on bank one, that rules out an ignition system fault, so Its either going to be a leak in the itake manifold gaskets, which is very common on this engine, or possibly a bad hose going to the PCV valve, which is also common, have you checked the elbow next to the PCV valve, its cracks very easily?