It is telling you that you are due for an oil change. When you get it done or do it yourself, make sure to reset the light.
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
the sensor is going out
check crank sensor
i doubt if you need an 02 sensor. try cleaning your mass air flow sensor with electronics celaner or brake cleaner first also check for vacuum leaks downstream from the maf
Engine Misfire? check engine light on? If so have vehicle scanned to determine the problem
Yes
it sounds like the oxygen sensor is bad or the throttle positioning sensor or even the mass air flow sensor. take the vehicle to an auto zone parts store or a checker store and they will read the code for free and you will know for sure. most likely it is the o2 sensor
you will need a fuel pressure and flow gauge and then check actual meaured to specs.
That is a warning light to "check your engine". Visit a mechanic and have them use a computer code reader to check for a trouble code. On a 2005 there is a good chance that you may have a bad sensor, such as an oxygen sensor.
Need to know what code(s) were set and which O2 sensor you changed in order to help you.
I have a Buick Regal LS and I had them run a computer diagnosis and it was due to the gas cap not fitting properly. There is an electronic sensor there. Most automotive stores will do this check for you free of charge.
What ar the symptoms? Check the fluid,is it full? What color is the fluid.