I have a '98 Civic LX with about 173,000 miles on it. About 2 years ago the engine light came on and the dealership said it was a bad catalytic converter. Since I didn't seem to have any performance issues and gas milage was unaffected, they told me it wouldn't hurt anything if I didn't get it replaced. A few months ago, I noticed I was losing about 50-60 miles a tank. Last week the light just went out, the car seemed to be driving better, and I was getting great milage again. After about 5 days and 2 tanks if gas (went out of town for the 4th), the light came back on last night. My big issue is that I don't want to spend $900+ to have it replaced, and I have to pass an e-check in Oct. (one where they just plug into the computer). If I do have to replace and spend the cash, what could have caused it, are there other things I need to check? Is this common for a '98 with this many miles?

Thanks for any help on this.

 

after 173,000 miles, your catalytic converter could very well need a replacement, however i would not look to the dealership for one untill your absolutly sure you can't get one anywhere else. Look online, call around..

these symtoms could also be from a bummed O2 sensor...

 

you can get a decent cat for about $100 from most performance shops or just get on from a junkyard.....much better than having dealer butt rape you

 

ahh, what engine modifications do you have??? because i believe if you have added a new intake system and/or a header, that can change the air/fuel ratio, and cause you to run richer, and the oem cat. wasn't designed to handle that...you should have replaced it when you first had the problem...to get an oem cat. would only cost you anywhere from $425-$450 i would think..about 2 years ago i had to replace mine and it cost me $440, so if you don't get an oem cat, you should look into getter a high flo cat, like a carsound or a powercore cat, those are at least designed to handle higher air/fuel ratios...anyway that's my 2 cents on this

 

Is this a totally stock motor?

My 99 hatch [D16Y7] has 200k+ on the clock and never once has the CEL flashed concerning the catalytic converter. I am also bone stock.

If the light is still on, get the 'blink' code and post that up.

What does the maintenance history look like concerning:

cap/rotor/plugs/wires
air filter
valve adjustment
O2 sensor

 

Car is 100% stock, no changes or additions. I've also followed the recommended maintnce schedule (give or take a few thousand miles). I'm the only owner, rolled it off the lot with 4 miles on it. I don't think it matters, but it is a 5-speed. And I'm proud to say that after 173k, still have the original clutch.

Calling around today to see what some of the local shops can do for me.

 

yea, i guess 173k miles might detriorate the catalytic converter...good luck man

 

Could be the cat at that mileage, but 9 times out of 10 it's the O2 sensor. Probably not related, but my work is handling claims for Chevron. Apparently they've been selling gas with too much sulfur, and it's damaged thousands of O2 sensors.