I have 34k miles on my mcs, and have had 2 o2 sensors go bad at different times. just got it back from service for the 2nd sensor being fixed and the check engine light came back on today (1 day after)!!!! Before I brought the car in, in the exhaust and sometimes in the car you can faintly smell like it is running richer than normal, the sort of un-burnt fuel exhaust smell - its a mild hint if anything. I am beginning to fear that my catalytic convertor is not working correctly. can anyone advise? I do some serious hard driving and have read that the innards can melt down and the cat will stop working effectively.

brains of MCO - unite!
thanks!
-ct

 

What software?

 

performance software? none, but i have the stumble, dont konw which software version though.

 

what is your gas mileage like? you can do a quick test by filling up the tank (double click it so that it is pretty well topped off) then drive 25 miles and refill.

 

My mileage has not gone down, just checked today, 25mpg with highway and some hard driving (i mean hard!) on the back roads