Maybe I missed it somewhere, but what pump are you running? I can't help with the OEM unit as I don't know anything about Zs, but I'd it's an aftermarket piece, make sure it's pushing your fuel and not pulling it. I've noriced that most like to be very close to the tank push fuel through the lines instead of pulling it through. If its working overtime and belligerently hot down there... It might be over heating.