Hi,
My service light is on and whenever it does come on before, i would just do the 4-1-5-1 thing and the light would go away. This time it's still on although i haven't changed the oil w/c is still due at the end of the month.
Could there be any other problem? By the way usually when the 4151 thing the red light would flicker indicating that the 4151 method is done but agan this time the light just stays on? The past few days there are times my tachometer reading is running wild from 800-1000. There was also a time the engine suddenly stalled when i was about to pull in from the ofc driveway and i was able to restart the engine after 3x. I think my fuel mixture is too rich? should i change the front o2 sensors? How do i know when O2 is bad and how do you replace them?

Thanks a lot
94 (Non turbo)850 wagon 210K miles