Engine Exhaust System problems of the 2004 Nissan Armada

My cats are going bad after I just spent $600 to get a whole new exhaust system! the car chokes up when I accelerate and almost feels like it will lose power. I also have a code coming up for p0430.

2004 Nissan Armada. Right exhaust manifold is cracked. Vehicle purchased 08/30/10 with 75,000 miles. At abeloff Nissan in bartonsville, PA. 09/07/2010 for back up sensor and control unit replacement. No other issues cited. 03. 08. 2011, miles: 83696 back at abeloff Nissan for ecm relay safety recall. Inspection done at that time. No exhaust leaks cited. 08/16/2011, miles: 89312, vehicle at local mechanic for state yearly inspection. Right exhaust manifold cracked, looks to have been cracked for a long time. I cannot believe that in 5616 miles, the exhaust manifold is cracking apart. Research online has shown a known problem with the Nissan titan/armada exhaust manifolds. I would like both left and right manifolds replaced by Nissan at no cost.

Both exhaust manifolds failed twice. At 40,000 miles and 80,000 miles. Nissan replaced under warranty at 40k with same defective manifolds which failed again at 80k. Nissan offered to replace with same defective parts for a total of $2400. 00. Leaks were discovered till 83k miles. I now own a vehicle that has consistently leaked carbon monoxide into the passeger cabin. My spouse is wondering if this was the cause of my six year old's brain cancer which was diagnosed 4 years ago when the manifolds were leaking for the first time. This vehicle has been her daily driver since new. It seems that Nissan Armada and titan vehicles have exhaust manifolds that fail between 30/40k and Nissan replaces with same defective part.

2004 Nissan Armada with cracked manifolds.

This is in regards to the exhaust manifolds. This is the second time I have had to replace them. The first time they were still under warranty. My 2004 Armada was at 66k miles. The Nissan deal that I took the vehicle too told me that Nissan has problems with their manifolds. They corrected the issue, but almost exactly 66k miles later the manifolds have again cracked. Now I am outside of warranty and required to pay for a replacement that is clearly a defect in the Nissan product. Manifolds should not be going bad after 66k miles.

Exhaust manifolds crack causing loss of power and CO intrusion into cabin. Had to replace at own expense. Known problem that Nissan has inconsistently addresses under warranty.