2013 Cascadia fuel problems, over fills the drivers side tank.

Had a 9300 do that off and on for a couple years. Replaced all fuel lines and splitter with no positive results. Would actually overfill drivers side until it spewed out but passenger side would run empty and suck air and you were done. Finally got angry one day at shop truck was almost out of fuel. Stuck shop vac into tank (150 gallon so hard to get everywhere) like a fool for a good half hour. Finally found in vac a small round piece of wax coated paper from inside cap of addative. You could actually see the raised area on surface where it would suck onto the draw tube. That thing was the literal bane of my existence for quite some time. Made me think about how simple things go unnoticed sometimes.

 

Idk, I was thinking the same thing when mine started leaking, but I decided just to replace it OEM