my 1995 GMC Sierra ext. cab 4 x 4 1500 SLE is hard on gas, Any suggestions to help? tires too big?

I had a '97 2WD that was hard on gas too. The only solution I could find was to sell it and get a newer one. I know that's not helpful. When your truck was built, gas was less than $1/gal. GMC had no reason to give you better economy than you're getting. You can change the tires to road tires, drop the tailgate, and never use the AC and you MIGHT get an extra mile or two per gallon.

Dropping the tailgate is a myth. Leaving it up actually creates an air pocket that moving air flows over more efficiently than if you were to drop the tailgate. I up'd my MPG in my 95 sierra with kn cold air intake, flowmasters, throttle body spacer. Obviously the key is to not use all the extra power they add and drive light-footed for better mileage.

The Not Using The AC to save gas is a myth as well.. when your driving down the road and you have the windows open you use more fuel than if you drive with the windows up and have the AC Running, this has bn tested multiple times and each time prove this to be accurate, it's due to drag.