SO last month I had a misfire problem that i got fixed $500 later and now since then my cat is starting to act up and throw a code that my catis running to lean. I know i need to replace it but is there anything else i can do like hollow it out and still run good. Since last month I also put in the APR chip and cant even really feel its full potential also about how long will it take to swap out the cat.

 

Won't take long but your cat wont run lean, its youre motor that runs lean. Sure its not an 02 sensor?

 

What code is it giving you?

 

We need to know the code?
How long did u run with the misfire ?
If you run to long you end up dumping alot of fuel
onto ur cat and it ends up working like a furnace, which
will destory it on the inside..
i would have a look at my O2 range and she wats happing

 

I forget the code it read out today it was trouble code 994 i think i could be wrong though. I was thinking it was the O2 sensor but i ran with the misfire for a few miles before i dumped it off at the shop and it ran like **** the whole way there. Plus it feels like the car is holding back

 

Def sounds like an 02 sensor then

 

If your O2s are old there would stick in the center or towards rich by default
and since you had a misfire the raw fuel can brake up the roadium in the
cat and coz a restriction in the exhrst...
Have you got the Misfire fixed yet ?

 

The misfire was fixed, the check engine light i turned off and hasnt been back on since i left work but who knows it could come on next time i start the car. Now would i replace both sensors or just one because theres one on the front of the cat and one on the back i believe.

 

wat engine is this ?
the is a Up stream and down stream
Befor and after
the would be 4 on the 2.8 I think
You have to have a look at the Data stream to know where to go next
see which one is moving slow in the Data stream
the have to move pretty fast to make changes to Fuel Trim

 

its the 1.8t i can check all this through the com tool correct?