What type of gas should I use in my Yukon

regular gas should be just fine for most stock vehicles you only need something higher for higher performance cars like a camaro or mustang and the such

regular gas will get you better fuel economy- ethanol is cheaper, but you lose 15-20% of your mileage (16mpg hwy instead of 20mpg why for example), so it has to be 40cents per gallon cheaper or more to be an option. I hope this helps.

I own an 1999 GMC YUKON, 1500. Lucky it was a one owner truck before me. I've been using 87 ..it performs well with ,slightly above average fuel performance.