hey guys,
i just dropped of the car at mitsubishi service because my SES light came on. later i got a call back from service saying my cat was damaged and needs to be replaced. they are holding my car till wednesday to confirm my car has not been tuned so my warranty can fix it. the car only has 7900 miles completely stock (never touched or tuned) but the cat needs to be replaced... i just find it a little wierd.
has anyone ran into this problem?
my concern is, the bad cat might be a symptom for a bigger problem.
hopefully they diagnose the cause instead of just replacing to prevent any future damage.

thanks for hearing me out

 

Did you purchase car used or new?

 

Not sure why it matters whether he or she got it new or used. If the car hasn't been tuned, then they have to replace the cat. If the car has been tuned, then he or she can try to argue that the tune didn't kill the cat (meow! ack!), but my guess is that the argument will be lost.

As to whether a bad cat on an untuned car is a sign of other problems ... I would check for a boost leak. If the intake only leaks at full boost, then you'll run even richer at WOT than a Mitsu normally runs and that could shorten the life of the cat. Other than that, I don't see this as a sign of a general problem.

 

^^
Car purchased new = never been tuned

Car purchased used = an unknown on whether it could have been tuned before purchase.....

 

Convoluted, but (now) understandable.

 

the car was bought new

 

If indeed the car was running rich enough to kill the cat, I would bet you would have gotten a rich condition fault far before cat failure.

No how would an intake leak at boost create a rich condition when it's under vacuum.. The so called leak u speak of would be actually sucking in unregistered air causing a leaner condition, wouldn't it?

 

Emphasis added.

The big error that I think that we all are making is taking the dealer's diagnosis too seriously. For all we know, the cat is fine and the second O2 sensor is bad. In fact, if I were forced to guess, that would be my first choice. But as long as it's under warranty and the OP doesn't mind waiting for his or her car, just dump it in their lap.