About 15 mpg on a 1990 Chevrolet suburban.
17/23
I average 15.8 MPG
I just drove from Ohio to Arizona with a 1989 GMC 2500 and averaged 15.5 mpg.
SUV's constructed by GMC offer a variety of miles per gallon ranging from the GMC Terrain that does approximately 30 miles per gallon on the highway to the large GMC Yukon that does approximately 25 miles per gallon. Also, the GMC Acadia will get around 16 to 18 mpg on day to day driving.
About 16 mpg city and 18 on the highway
21
my 2001 4.3 rwd safari gets 18-20 mpg
1990 Chevrolet suburban gets about 15 mpg.
The EPA mileage estimate for the 2009 GMC Savana is 13 mpg in the city, 16 mpg on the highway.
The EPA mileage estimate for the 2007 GMC Savana is 13 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2012 GMC Yukon is 15 mpg in the city, 21 mpg on the highway.