i just ran a test on my ecu and i got the o2 sensor code....

i have 100k on my 98 max and i plan on replacing the front 2 o2 sensors....i get about 18mpg with mostly 80% highway driving

the question i have is "have u guys repalced ur cat?' if so when.....how do u know when exactly to repalce it?

does repalcing the cat have any effect on the gas mileage?

 

still running the original cat but damn does it smell at times

i am thinking of replacing it but having gotten around to it.....

 

I have 61k on mine, and i am replacing the cat, along with the rest of the exhaust. The hanger on the B pipe broke on mine, which is making it bang against the cross member, along with most of the exhaust being corroded. Everything from the y pipe to the muffler is begin replaced. Alot of it definitely had to do with what part of the country your car is in. I have seen guys on here with 100k+ on their car, and they have no where near as much corrosion on their car parts as I do. Northeast weather sucks.

 

i have a test pipe sitting at my house never used has the o2 hole pm me

 

naw, no test pipe for me

but i am interested in how long many miles the stock cat is good for

i hear it is illegal for exhaust shops to tamper with any catalytic part that has under 100K on it

 

I think it is anything under 60k on the cat and you start to tamper with it is illegal, I just want to remove the cat completly and put a straight pipe their, would the engine not like this? Because here in the great state of Montana emissions do NOT matter at all. I know the muffler shops around here frown upon the fact of messing with cat's but you still can.

 

If you don't have emissions, I dont know why it would be illegal to have one. The main purpose of the cat converter is to take all of the chemicals in your exhaust, and purify them so they dont pollute the environment. Unless you are big into the environment, I dont know why you wouldnt be able to use a test pipe. I have heard about big differences in exhaust noise using the test pipe, which is why i dont want one.

 

To the guys that have replaced their cats, which one did you buy?

 

i have 127k with the stock cat. just put a y pipe on. i looked at the cat when i took it out. it's still clean inside not broken up at all. the car has only ever had 93 octane in it. my o2 and knock sensors just went, along with my gas mileage.