IF my O2 sensor or my knock sensor is bad, how will i know this and what will it do to the preformance of my car.

 

Run a diagnostic on your computer. If any stored codes come up pertaining to an O2 or knock sensor, then you'll know what to do. Sometimes this is not the case in which you'll just have take a chance, change um, and see if it works. Good luck.

 

A bad oxygen sensor/knock sensor will greatly decrease your gas mileage, and hurt performance as it causes your car to run rich.

-Sryth...
__________________________________________________ ____________________________
'98 SE 5spd, Pebble Beige, PRCAI, Stillen Y, Stillen FSTB, ACT clutch.
Pacesetter STS to be installed this week!

 

i think you'll knkow if the knock and o2 sensors are bad by ecu codes. Mine are running bad because of spark plugs, atleast i think. My gas mileage is pretty bad. I am halfway done in my gas tank and i have only put about 135 miles in. I have been flooring it and i do drive stick so i do rev up a lot but this will put me at like 280 miles per tank maximum when i see others going well over 300....

 

If either of those sensors are bad and there is a code on the ECU, would the engine check light came on?


Thanks...

 

I've heard of people pulling these codes with no CEL, so I'd assume it's possible. Just to be safe, I check my ECU at every tune-up.

 

sryth,
thanks for the response.


slammed95,
did you see a gradual decrease in gas mileage with or with out the CEL on? or did your gas mileage suddenly drop to 220-235 mpg and the CEL go on?

my car suddenly dropped about 50 mpg but the CEL is not on. i didn't check for any codes yet and i will, but for now i'm just asking. any info appreciated.


thanks,

 

More than likely, it's a bad O2 sensor. A bad knock sensor should result in retarded timing, which hurts power but generally doesn't significantly hurt mpg. The ECU might have the ks code but not turn on the CEL. I don't know what to make of my O2 experience...But I had been getting about 24 mpg (75% highway, 25% city) for as long as I can remember. After my CEL was kicked off due to O2 sensors, and I changed them both (front/rear banks), my mpg went up to 26.

 

my gas mileage has been terrible since I've got my max in may. I'll get like 200-250 miles per tank (however I do floor it all the time which doesnt help) I think the fuel filter is bad, and its probably time to pull up some codes from the ecu to see if anything bad is going on in there.