I went to fill my tank with gas and the pump did what it's supposed to shut off when tank is full,well my friend said that the needle went to F,but when i got into the car to start it up it read 3/4 tank?! Any suggestions? I took it by the dealership and they told me that it would take all day for them to find the problem and that i should schedule an appt.OK,but it felt like they didn't believe me. This was an issue with my '05 Trailblazer.! Has anyone ever had a problem with their tank/guage?