Service Indicator Lights on?

Two years ago, my Check Engine Light came on. The mechanic said that both A/F sensors needed to be replaced but it was very expensive. This may affect my fuel efficiency but doesn't seem to affect anything else. I opted not to have the repair done. The Check Engine Light was not reset because I didn't have the repair done. Just a few days later the light went off on its own and didn't return for two years. But during those two years I saw the low tire pressure indicator light come on and off several times even though my tire pressure was fine, and I even saw the low engine oil light come one once even though my oil level was fine. The lights never stayed on for long. Just recently the Check Engine Light came back on but only stayed on for a day and now it is off again. My questions are, could there be a short in the wiring that is causing these lights to come on and off? If I truly have a problem that the 'Check Engine Light' comes on for, would it be the same problem that they diagnosed two years ago since the light never got reset? What would you recommend I do at this point so that I don't see these random lights come on? Thank you!