Same issue here. Had the manifold replaced under warranty at 100k miles. 35k miles later and car throwing p2015. Took back to the dealer that replaced the original failed manifold under warranty, they tell me I have a defective one and will need to replace with a newer revision. However, not under warranty, it will cost $800...... I argue they put in the faulty one, they refuse to replace it! FML
zrickety, can you please post a link to the ARP solution? I may have to try this out before I undertake the entire manifold replacement myself.
Thanks in advance.