2000 Emission problem

egillettegillett Member Posts: 14
edited March 2014 in Chevrolet
The "check engine" light comes on and the code indicates a problem with the vapor system. Gas cap is good and the problem will go away at times for 400 or 500 miles and then the light comes back on.
I was wondering what others have found to be the cause if they have experienced problems with vapor system. Thank you in advance!
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