i have a 98 integra ls. i got it about 2 months ago. it feels pretty strong but i noticed it was kinda low on oil about two weeks after i got it. the guy had the oil changed about 1500 miles ago so i just added half a quart and it was fine. well yesterday my oil light came on so i went to the closest place i could find a bought oil. it took 2 quarts to get it back almost full. I have driven about 2000 miles since adding the original half quart. i have no visible leaks. i checked under the car and cant find anywhere it is leaking so i assume its burning it. i replaced the pcv valve 3 weeks ago thinking that might be the problem but apparently it did help. i use 5w30 full synthetic oil. not sure if this affects it but i have a bad o2 sensor. i havent noticed any smoke from my exhaust unless the car is cold. then some dark grey smoke comes out till it warms up but not a lot of it. what could be causing my motor to burn this much oil?