The phrase "gas hog" is used to describe a vehicle that uses a lot of gasoline. Essentially, it means that the vehicle consumes fuel quickly or isn't very fuel-efficient. Full definition
Swapping gas hogs for more efficient new vehicles was a major goal of the «clunkers» legislation. (automobilemag.com)
It was time to trade in my mother's gas hogging SUV for a new hybrid. (autolist.com)
My take on the Nissan Titan; No advertising as Buzzerd said, but more importantly, it has changed very little since it's introduction.One of my son - in - laws just bought one two years ago and loves it, but admits it is a huge gas hog, like the Tundra. (autoline.tv)