With my 2013 extended cab on a lift to install a primary pump I noticed that the fuel return line had a crimp in it where it does a slight upturn just about under the driver door hinge and it's covered with a plastic braid. No obvious symptoms for me but may cause some for those with tuners. This was obviously a production flaw so there may be more of the same out there. Dealer agreed it was covered by warranty. Of course I put off touching the fuel system until AFTER the fix.