i have a 2008 infiniti g35 the gas gauge doesnt read right and about a year ago i took the pumps out and cleaned the graph looking thing, it made it closer to right but not exact. anyway yesterday my car quit running and would not start and had to be towed and seemed as if it wasnt getting gas so i put about 1 gallon in it and it started up. there was approx 7 gallons in the tank but wouldnt start until i added gas?

 

Can you explain this part a little better?