I posted this in Off-Topic because it refers to all Mazda's, not just protege's, and not just third gens. Yesterday, while at the Mall not laboring, on labor day... My CEL (check engine light) came on... I figured it was another MAF malfunction, so I went home, cleaned the MAF, and reset the ECU. The light went away for about four hours, then came back on. Well... I kept staring at my gas gauge for some reason, couldn't figure out why in the back of my head, this would trigger a CEL. Well, it kicked in today while driving home from work. I remember from when I snapped a bolt on the valve-cover, the tech who drove me to work in another customers MPV, told me the MPV was having a problem... when it got to 1/4 tank of gas, the CEL would come on. So, i'm sittin just below 1/4 tank, and decided to stop at the gas station to test this... sure enough, when I filled her up the CEL went away. Does anyone know why this happens, or have you had this happen to you before in your Mazda? sorry for the long post.

 

how can i tell? as far as i know, the cap is fine.. it's not chipped, cracked, and seems to be in working order.. it still screws in. lol.