3 cats, 2 $1200, 1 $400

[atx]

ok so i guess my 99v6 is throwing a code of broken cat, not a 02 sensor or anything supposidly, its a reputible place but it always doubt. hes sayin its a mystery which cat it is, and one is $400 the cheap one. .. and theres 2 more that cost $1200 i konw we have 3 but it just sounds rediculous fill me int a bit, thanks!

[WarmAndSCSI]

99 V6 should be fed-spec and just have 1 cat that's pretty cheap, but in the case that you do have a Cali-spec 3-cat model:

There are 3 cats and you need to find a new mechanic if he's even suggesting the OBD-II code could be related to the secondary cat (the single one that costs $400). I guess if it were EXTREMELY clogged you could be seeing catalyst efficiency codes on the front cats, but the car would have its power output cut in half at that point.

Hell, it could just be the O2 sensor. Your mechanic should be diagnosing these items by doing back pressure tests, etc rather than just relying on the OBD-II code that's being thrown up. A bad O2 sensor can lead to a bad catalytic converter, however (dumping fuel), so it's always good to check both.

It's my opinion that this reputable shop is trying to waste your money or they seriously don't know what they're doing.

[6G72gearhead]

I got a catylist efficiency below threshold code awhile back, and it was the cat causing it. They replaced the cat under warrenty and it went away.

It should only be 1 cat thats causing it, they wont just both go out at the same time like that unless something is seriously wrong.

[atx]

there saying they wont know which one is having problems till they replace one, then if still problem do another

[stkiflngaz]

which code is it throwing up
should tell you what bank and sensor it is
i would check the o2 sensor first for around $150 instead of going straight to the expensive cat
could just be a bad o2, it happened to me