The check engine light in my 2004 Corolla with only 34,000 miles on it came on a week or so ago. The guy told me it read an evaporative emissions code but he didn't tell me which one. Told me to tighten gas cap and he cleared the code, but said if it came back on to take it to a mechanic. It just recently came back on. Has anyone else had this problem?? Any advice or insight would be helpful