[Fbks_Cruiser]

I can’t answer you question about which is the correct cap or what to do with your eec but I can tell you what I did with my cap. When I bought my truck several years ago, the cap that was on it leaked. With a full tank, gas spilled out when cornering. I went to the auto parts store and bought a new one. Problem solved - for a year or so. The rubber in the new cap was crap, it deteriorated and started to leak. So, I cut my own seal from some sheet rubber I had in the garage. No leaks for several years now.

You should be able to repair your cap in the same way. A new seal should make it fit tighter.