Hello, I have a 98 GS400 and I need a new catalytic converter. I’m trying to get the car from my grandparents and it’s due for inspection in august. So I had to get an inspection now to put the car on my insurance but I kinda layed off on it and now it needs a new catalytic converter.(Check engine light came on and I checked it with a scan tool). It’s my first car and i’m still in highschool so I don’t have a lot of money and it has 278k miles on it. never has had an engine problem or anything. Has had some other small issues but other than that it has been great.

Went to a shop and they said to check it out it’s 150$ and to replace it since apparently there’s 2 catalytic converters it will be 2k. although if they look and see only one is bad then they can only replace one and i’ll pay 1k.
Also they told me that if I fail the inspection test and spend over 700 to fix the problem and re test and it still fails, I can fill out a state form and it will exempt it and it will pass.
What do you all think is the best approach here?

I technically have till august till it needs an inspection so really I have time to figure it out.

Here’s kinda my options from how I see it:

1. get it checked for 150$ to narrow down if it’s 2 or 1 that need replacing and then save up hellas and get it fixed.

2. find someone cheap to do it. My uncle knows some people who could help do it or something.

3. idk, fix it and if it does fail, I can fill out that state form?

4. try to do it myself.

Let me know what you all think.
Thanks.
-Mo

 

Here is your flowchart:

Do you think you are able to and are you willing to fix it yourself? If yes, fix it yourself.

Otherwise, do you feel like the amount of money it will cost to pay the shop to do it for you is worth it, and do you trust the shop to be able to fix it properly? If yes, have them do it.

Otherwise, get rid of the car.

Some notes:
- Be absolutely sure that replacing one or more cats will actually fix the problem before taking any of the above steps.
- You will probably be able to get a replacement cat for a whole lot cheaper than what the shop quoted you by buying second hand / off ebay or the like / or from a pick n pull.

 

This. Do you know for a fact it’s a bad cat and not an O2 sensor or a bad gasket?

 

i’ve looked into it a little more and i’m pretty sure it’s just an O2 sensor. Scan tool told me it’s bank 2 so I mean I could probably just replace both of those O2 sensors and it should fix the problem. I looked into how to replace them and it’s definitely not easy… but its possible.
I guess it’s good news since it’s definitely cheaper than a cat.

 

99.99% of the time when the GS throws a P0420 code or any code that mentions that catalytic converter not operating properly, most mechanics tell you it’s the cats because they are straight ignorant and lazy. It’s almost always the O2 sensors.

 

Not all the time because I chased this down on my car a few months ago. The code is actually correct, because it’s stating the cat is operating under the minimum efficiency, which is expected because the cat is over 20 years old, BUT it doesn’t mean that it needs to be replaced. Most times this code could be triggered by a leaking gasket. I replaced both upstream and downstream O2 and that didn’t fix it. Hell I even removed the downstream cat because I thought it was clogged, and was about to purchase a cat. The code didn’t go away until I installed an O2 spacer with the new O2 sensor.

 

So basically you didn't fix it but just made it impossible for your car to keep detecting the problem..

 

Bingo! If the efficiency is 95% but it’s filtering at 93%, I won’t change jt. Hell, I’m not spending $4k for a brand new OEM cat when the car is over 22 years old…