Hi everyone,

2008 XK coupe, 139,000 miles. Car came with an aftermarket Amadesh exhaust.

I have p0411, p0171, and p0174 codes. I've replaced the intake plenum (riddled with cracks), and the throttle body gasket. I replaced a leaking EGR valve and both EGR gaskets. I have the intake manifold gaskets in the mail. All vacuum lines are new or in fine shape. Smoke tested.

I have a ticking sound that changes as the car warms up, and I get a lot of throttle hang when the car is cold. Presumably an exhaust leak. If I drive for a while, like the highway, my CEL stays off, but I get pending P0171/P0174 codes. I am praying that the leak is somehow on both pre-cat exhaust gaskets. I'm dreading the possibility of having to do the exhaust manifolds. I have access to a lift, so anything is doable. Has anyone on here done the exhaust manifolds before? Any strategies? Looks tight in there, lift or no lift.

As for the P0411 code, I had hoped the replacement EGR valve would fix it, but its still there. How can I test the relays for the smog pump?

Thanks for the help!

 

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The X150 was introduced in 2006, and since then almost every question has been asked and answered. Learn to use the Advanced Search function or find answers to your questions using Google. Simply preface your Google search with "Jaguar X150 Forums" followed by a few key words. For example, you could Google "Jaguar X150 Forums exhaust manifolds". I don't remember any threads about exhaust manifolds, except for replacing them with headers (which is prohibitively expensive).

Good luck finding the answers to your questions, and I hope you enjoy your XK as much as I've enjoyed mine.

Stuart

 

Welcome @2008xkowner .

Firstly, the codes you present are generic codes and lack the JLR component to the code. Moreover, there are JLR specific codes that your reader may not be equipped to report.
If this is exhaust related, I highly doubt it is exhaust manifolds and more likely clogged cats... (but no O2 codes...)

But I wouldn't go there first. I would confirm a clean PCV valve, MAF, and a clean filter. Followed by a ECM reset, and a test drive, as per the manual.
It is essential that the air intake system is airtight between the MAF and the intake manifold.

Do you have the Workshop Manual??

 

Don't forget a Hard Reset.