When i go to put gas in the gas backs up into the fill tube and shuts the pump off ,then when i pull the nozzle out in can hear air being sucked into the tank. also this morning when i took the gas cap off it sucked air into the tank again ,, also i got an tighten gas cap warning on the dash ,which i did and nothing happened. then i got a check engine light.
any ideas ??
thanks
jeff

 

There is a solenoid that runs a valve for the evap system. Vapor inside the gas tank pressures up especially when its hot out. So it is thrown into the intake of the motor. Then the valve opens to let in fresh air for displacement. This valve is supposed to open when you fill up, to let out pressure. Ever notice when you do fill up you smell the gas? Thats mostly why. So have the codes checked and see if you get a EVAP code.