I had a 99 full sized extend cab Chevy 4X4 that I got about 18 mpg with and decided to try a new Sonoma to, hopefully, save a bit on gas. Bought a new crew cab 4X4, V-6 Sonoma in 2001. Got 16 mpg on the highway and as soon as warranty ran out it started costing me money on repairs. And I ain't talking cheap repairs, either. Went back to full size.