I have a 2002 Jeep liberty, 3.7 L gas engine with 99,000 miles. The oil light came on so I took it to my mechanic. I was using a semi-synthetic oil, he took it out and put the factory recommended oil in it. Light went out for about an hour then came back on. Next he changed the sensor, light went off for about 10 minutes after I got the car back. Now it comes on and blinks for a while then stays on steady. I don't know where to go from here, my mechanic is not sure either, any ideas?