Here's the deal (since it's the same engine that's in my Sentra):
The QR25DE engine has a flaw. Not the engine itself, but the exhaust.
They put the precat in the manifold really close to the engine/exhaust ports on the head so it would heat up quicker for emissions and stuff.
Well, there is a protective layer on top that keeps the catalyst in... this protective layer breaks down with heat.
After this happens, the engine will end up sucking the catalyst in via the exhaust valves at high RPM (guess this has to do with the variable valve timing), which wears the cylinder walls and causes high oil consumption. If this person doesn't check their oil...I'm sure you can figure out the rest.
Only fix for it after all that is a new engine since the block is toast.
It's been happening since 2002, but they apparantly have been using the same manifold/precat setup on all the engines. I'm guessing they were forced to recall due to a very high number of engine replacements done under warranty for excessive oil consumption.
There is preventive maintenance for this, which involves you taking off the manifold and doing the same "Mystery Mod" for Contours or putting a non-cat header on there. S-tune parts will not void the warranty, btw.
