Car had been throwing p0050 code at me for a while. Changed o2 sensor with cheap online model. It took away my check engine light, and everything was fine for 2 months. Noticed a rough idle and check engine light on again this week. Checked codes and i'm getting the p0050 again, plus a p0155 and p0150. Any ideas? i'm a bad backyard mechanic at best. But trying to do as much myself as i can...PLEASE HELP! Checked ems fuse and it looks fine. Check engine light didn't come back on after reset for a 30 min drive. As soon as i restarted...check engine light on again.