How do I troubleshoot a fuel gauge error? on 2007 Isuzu Ascender

I have a 2007 Isuzu Ascender that after approximately 30-70 miles on a full tank of gas, the gauge reads empty and the low fuel light comes on. Is this a bad tank sensor? How do I troubleshoot this?

Asked by for the 2007 Isuzu Ascender
ground the power wire going to the sending unit the gauge should go to full
1 more answer
possible sender failure. may have to replace sender.