Toyota 4runner catalytic converter replacement

No it is not under emissions warranty the year is what is the factor, it is 7 years or 70,000 mile whichever comes first. You need the check engine fault code read and that fixed first, it is most likely the cause of the smell from the catalytic converter which is caused by a overly rich fuel air mixture. The fact you smelled the sulfur indicates the Cat is working. I was a certified repair and inspection technician for the Calif smog control program for 35 years.

I would first want to know if the sensor is actually failing. A trouble code for a sensor is not a sign the sensor needs to be replaced, only that the data coming from the sensor is out of normal range.

if they look identical in every way

Chris,

Try checking the catalytic converter. A plugged or damaged cat can cause low power and poor fuel mileage. Hope this helps =)

have you had the air mass sensor checked?

NO, a cat only cleans up pollutants. It has no effect on engine performance unless you have a misfire and the cat works overtime and melts and cloggs the exhaust system. If your blowing grey smoke out the tailpipe then you indeed may have a bad engine. What I would want to know from the mechanic is what is the compression and why he thinks its a lower engine issue rather than a leaking valve on the head which would be alot less expensive to repair. Then again you could get a second opinion from another shop. Mechanic shops are known for gouging customers wallets, Not that i'm implying anything here.

Bank 1 is the same side that cylinder 1 is on which should be passenger side. Sensor 1 is right in front of the catalytic converter,and sensor 2 is after the converter.

well it if it has 2 cats they it is likely california emitions
and if it is best to replace both the keep abck presure even accros the motor

Not sure, but did you replace the oxygen sensors. Is your catalytic converter still good?

Cool. You have no problems getting it welded.
Please tell me, which dealer wanted to seel you a cat? I have connection with Toyota HQ, they need to know this stuff. Selling you a cat is simply BS.
The graciousness of a FixYa rating would be most appreciated.