Hi, I'm Steven. I have a 2000 LS with the check engine light on. Had the light checked and was told that it was the egr valve. Simple enough. Replaced the valve and had the light turned off. In a couple of days the light comes back on so I go by the auto parts store for another check and he says it's the egr. I told him I just replaced it and cleared the memory. He said that I also needed to clear the history so he did that for me. The next morning the light came back on. Car is running fine. What gives?