Let The Beat Build Tha Carter III Lil Wayne

givin' me this diesel like a F-350

The producer of the song is a New Orleans producer named "Deezle".Wayne previously says.." i gotta thank Deezle for giving me this Deisel. Its a wordplay of the producers name, and how Deisel fuel makes a F-350 drive.The Beat makes Wayne be able to rap
He's saying someone gave him the hot beat. When he says diesel it's something similar to fire (hot beat), also talking about diesel gas which goes into the F-350 pickup truck.
He's talking about getting weed (sour diesel is a popular type). Then the next line is "Like an F-350, tank never empty" meaning that he always has weed. F-350's have a large fuel tank..