Very good info, I have the issue you describe when I remove my gas cap. What’s the AC Delco PN?View attachment 2915756
Not sure about the fj62 but this is where the 60 charcoal canister is located (passenger side).
In the 60 it only affects the carb by allowing it to vent the fuel bowl. From my understanding, the other hookups would impact any motor regardless of fuel delivery method. It allows your tank to breathe through heating and cooling cycles and prevents pressure buildup in the tank. If there’s a rush of air when you remove the gas cap I’d recommend changing it out.