Jaguar Repair Questions? Ask a Mechanic for Answers ASAP
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I think we have more than one problem. We most likely have a vacuum leak causing the rough idle when cold. The intake gaskets leak causing this. FOr the code P0430 the front cat converter will need to be replaced and the vacuum leak most likely caused the converter failure.
We need to check for a vacuum leak first as this will cause the engine to run rough when cold. Start the engine and listen for any hissing or air noise from the engine on a cold start. I see you already replaced some seals but the upper and lower gaskets leak, booster hose, IMT seals and the orings at the bottom of the booster and purge quick connect fittings all leak when cold. The PCV tube also splits but you would have most likely already seen/heard that. Please lets check for a leak first. Then we can clear the code to see if the cat fault code returns.