For about a year when I get gas the flow of fuel into the tank is interrupted and the pump cuts off several times during fueling. This problem started when I mistaken put silver instead of premium in the tank. Could the problem be related? The gas station attendant says it may be air in the fuel line. Any other ideas as to what it could be?

 

The shut-off feature is a function of the nozzle and a valve in the pump. Have you experienced this problem at a particular gas station, where all the pumps are the same model, or at any gas station? Do you fill the tank at the maximum rate? Try filling at a slower rate each time until the problem goes away. If the flow is way too low, there may be blockage in the filler tube causing gas to back up. Using different grades of fuel would not cause any harm to the car, except for a slight loss of power when using lower grades.