Put Amsoil ASM 0w-20 in my 98 LSC. My car has an onboard message center with real time MPG calculations which is very accurate. I was impressed with the MPG gain compared to even the Mobil 1 Racing 0w-30. At 60mph cruising on the freeway I would get around 28mpg, today with the ASM I was getting well over 30mpg (30.4). The engine seems to love it. The one thing I was surprised about is it too 6.8 quarts to get a full reading on the dipstick when it usually takes 6.5 with other oils?