I have a 2001 3.8 liter, we used to get appx 20 MPG, now it has dropped to Appx 16-17 depending on gas, I did tune-up, tire pressure, gas filter,etc. basic stuff. I do smell slight gas fumes when I start the Van, engine light is not on, could it be a problem with the oxygen mixture or something similar ?

Thanks for anyhelp

Rich

 

Are going to the same gas station for your fuel? The problem could be the blend of fuel switching from winter to summer.