Have problem with tanks

Replace the tank vents, they are not very expensive. Fuel caps could be bad. Have fuel pick up and return lines checked. Lastly, I have seen a piece of plastic in a fuel tank cause your problem.

 

atleast on my peterbilt . you can replace the orings on the fuel caps.. if they are rotted out or cracked they will not create a good seal... most likely on a newer truck like you have.. its going to be vents or u have some crap plugged in the system somewhere... if truck was sitting awhile the new biodiesel plugs stuff up fairly easily.

 

I would be red around the as