alright my 1997 cavalier has always been weird with oil ive had times where it went through a lot of oil and times where it lasted, lately my oil light has been on but is only was on when it was sitting idol but when it was driving the light went off and i thought it might be the oil pressure sensor, i mean it;s never leaked oil and ive never seen oil underneath it. So now about 2 weeks ago it went from oil light to only check engine light? and i say 2 weeks ago cauz that's the last day i drove it now it's sitting.

 

the sensor may be coming on at idle because the oil pressure drops a bit, when was the last time you changed your oil? and how many kms are on it? does it idle for long periods?
answer these and i can help u better

 

There is no tie between the check engine light and oil light. Check engine light is for emissions sensors / computer. The oil light has to due with the pressure of the oil. It could be the oil pressure sensor or more likely it does not have enough pressure at idle from being run low on one too many time.

 

that's only happened onece, but the wierd thing is that it randomly will run low on oil and their is no leak? like it's gone 100's of miles and been fine one point and then go 200 other miles a diff day and be almost out