I've looked but couldn't find an exact answer. I have to replace my O2 sensor after the cat. From what I have read it best to replace both at the same time. Now my question is I may have to replace the exhaust. Would it be best to wait and do all of it at the same time, or is there any harm in replacing the O2 sensors now and the exhaust later? I recall something about contaminating the O2 sensors or something.

 

why do you think the down stream O2 sensor is bad?

 

^^x2
Vehicle info pls. Do you have a check engine light? what is wrong with your exhaust?

 

Sulfur, I am a product specialist with Walker Products, a manufacturer and worldwide distributor of oxygen sensors. It is not particularly bad for you to replace your rear O2’s now and then replace the rear exhaust at a later date, though it would be ideal to do both at the same time. Unfortunately, whenever you replace your cats, there is a risk of contaminating your new O2’s from the coating inside the cat converter. I hope this helps.

 

Thanks for the replys yall. I just bought my jeep its a 96 waiting on build sheet. Bought it with the check engine light on and the seller told me it was the O2 sensor. The jeep runs fine, but has that exhaust rattle like the cat is going. I had the auto parts store run a check of the trouble codes, and it's comming up the rear O2 sensor. So I was thinking about upgrading the exhaust manafold, cat, muffler, and all the pipes, as well as both O2 sensors. I have just been debating on doing it in stages or all at once. I just remembered hearing something about needing to change the O2 sensors when you swap out all the exhaust componets at once. Thanks for the heads up on the new cat contaminating the O2 sensor.

 

I would suggest doing the manifold first, then do everything behind it and leave the old downstream o2 sensors in, then replace that however long after so it isn't wrecked. I'm in the middle of doing mine right now as well. Do you know if the upstream and downstream sensors are the same? If so could you put the upstream downstream and just have to replace the one.

I think a broken exhaust manifold might mess with a new upstream o2 sensor as well so you may want to keep that in mind.

 

Do all at once,youll break something prob just changing the o2(i broke my hanger on crossmember and cracked manifold when i had to remove the pipe where po stripped o2 thread). I would do everything and drive with a plug in rear o2 spot for awhile then put rear in

 

Rockauto.com get front and rear for price of one at AZ

 

Stop by your Jeep dealer and run the VIN. There is still an active campaign on the '96 cats. You *may* qualify for a no-cost replacement.


August 2006 Dealer Service Instructions for:
Emissions Recall E22 Reprogram PCM and Inspect Catalytic Converter

1996 (XJ) Jeep® Cherokee
1996 (ZJ) Jeep® Grand Cherokee
NOTE: This recall applies only to the above vehicles equipped with a 4.0L (ERH) engine.

1997 - 1998 (AN) Dodge Dakota
1997 - 1998 (XJ) Jeep® Cherokee
1997 – 1998 (TJ) Jeep® Wrangler (built after June 30, 1996)
NOTE: This recall applies only to the above vehicles equipped with a 2.5L (EPE) engine.

IMPORTANT: Some of the involved vehicles may be in dealer used vehicle inventory. Dealers should complete this recall service on these vehicles before retail delivery. Dealers should also perform this recall on vehicles in for service. Involved vehicles can be determined by using the VIP inquiry process.

Subject
The Powertain Control Module (PCM) on about 467,400 of the above vehicles may not be capable of detecting a deteriorating catalytic converter. Also, under certain conditions, some catalytic converters may be subject to mechanical degradation that causes a rattle.

© Copyright 2006, DaimlerChrysler Corporation, All Rights Reserved
**************************************…

 

thanks will look into that.

 

then again its got 185k mi on it and I not sure I want the dealer screwing with the pcm? Cats are not 300 dollars any more.

 

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