4 Wheel Drive/SUVs: fluids, o2 sensors, gas mileage

Question
I own a gmc 2005 1500 sierra crew cab 4x4.  I was wondering if changing all fluids to synthetic would help gas mileage?  Any other suggestions?  Thanks

Answer
Yes,

The synthetic fluids have much more lubricity and break down slower than oil does. This will help with gas mileage. Other things to consider would be to replace the air filter with a high flow filter like a K&N or equivalent, Make sure your O2 sensors are in good working order and the air pressure in the tires are up all the way. Plus make sure all accesory fluids ( power steering) are full as this will cause excssive engine load and kill mileage