I had defective Fuel senders @ 8k on my '09.
Problem is, if the Tech doesn't "see" the issue himself, they are hesitant to fix it.
The dealer spent a few hours "inspecting" the car, and didn't find anything so I drove to a local gas station with a Tech sitting shotgun and he saw with his own eyes the fuel gauge not liighting up. The Service Advisor had no choice but to order the parts and ok the fix
P.S. This was a big problem on the 350z's and a buddy of mine went thru 3 sender units within 36k mi. warranty and at 38k it failed again. Once his gauge hits mid tank, it just drops