Do you think a crack from catalytic will cause failure to sensor. My lights stayed on even i reset the battery. It was a couple of days my light warned and today again. I feel the idle was different .the RpM goes up right away even i accellerate the gas moderately. and when i check my oil now is dark w/e not usually the color. Is it because i ran the car even the warning is on.Do i need to change my MAF? If O2 sensor w/e one normally die right away..Pls...i need advice . I already repaired this car twice and got advice from this column it saved me a lot of money. I already change the CPS and brake sensor.