I was looking at the 2007 gmc and one of the specs was a 6.0l vortec and it says it runs diesel fuel. And it even has a diesel cap on its tank. Here's the deal that year up to today the Diesel engine is a duramax and the gas engine is a v8 vortec. Keep this in mind you put the wrong fuel in your truck it's over for that engine if you run it too long on that tank.