Another PO420 question and Catalytic converter replacement

[dirtyvelo]

So the story goes like this; I blew out the engine on my 2001 4X4 4runner with 250,000 on her this summer and had a used engine with 50k put in and it runs great. That is until the other day when I jumped in to start it and it just kept turning over and wouldn't start. I finally got it started by pumping the gas peddle numerous times. The check engine light had come on a few days before, but I had not done anything about it. So I drove it down to the mechanic, who had replace the engine, and he said that I was throwing a Po420 code and that I more than likely need a new Cat seeing that we had replaced the front o2 sensor the year before the engine blew. I told him I couldn't afford the Cat, so he did an "exhaust fluse" and turned the code off. The check engine light stayed off for about a month and a half but poped back on yesterday. I don't know if this could be the culprit, but the Runner still has the original rear o2 sensor.

I have notice that the Runner doen't crank up as fast as it used to and seems to run a little rough. The gas milage has also dropped from 19 to 17mpg since the sensor kicked on.

So what are the chances i'm going to have to replace the Cat? Is that something I can do myself seeing that it is just bolted on? Also I notice that there is (at least what looks to be) a front and back catalytic converter. Do I need to replace both? If I do need to replace the Cat, any suggestions on a place to buy a long lasting aftermarket Cat?

Thanks in advance!
J.Rice

 

[Supra725]

I had an similar situatuion too.

My check engine light would just keeping coming on, I cleared it one day and it comes back the next.. It never ended..

Until the 2 months ago, I changed out the front and back O2's with Denso.

What emission is it? is it an cali 4runner?

 

[nyc4runnin]

i think all 3rd gen t4rs 2000+ are all cali spec, only 99's were half cali/ half federal, perhaps he got an older engine ( pre 99) ??

 

[dirtyvelo]

Im located in Tennessee, so Cali regulations don't apply.
Im rather sure the catalytic converter did not get replaced when the engine was switched out. I looked under the Runner today and there are defiantly two definable sections with a o2 sensor attached to each section. I attached links below to what they look like. I can also see that the front o2 still look fresh and was replaced last year with what looks like an OEM o2 sensor and the rear one looks old and dirty on the outside.

Front segment looks like this:
1999-2002 Toyota 4Runner Catalytic Converter - Eastern - Front, Stainless steel, Direct OE replacement

Rear segment looks like this: 1999-2000 Toyota 4Runner Catalytic Converter - Eastern - Rear, Stainless steel, Direct OE replacement