when gas cap is removed it has a surge of pressure come from the filler tube. could this be the vent plugged? and where is the vent? the check engine light comes on when car is started and remains on while it is running,i am not sure if these 2 items are related though. i bought this car for my daughter 3 years ago and she 'gave' it back to me after she got an altima a few weeks back. the car has 171K on it and i just plan on driving back and forth to work in it mostly so i can let my silverado set(and save on fuel costs). has anybody had this happen or know what i need to start checking to solve this 'pressure' problem....thanks in advance!