The HEMI is also 5.7L and not direct injected. It also has higher specific output (395HP/410lb-ft vs 381HP/401lb-ft). The Tundra is just hard(er) on fuel. I'd say The Critic's point about deeper gearing is probably bang-on, as that would definitely be a contributor.Tundras get bad mileage for 2 reasons: 1. Not direct injection. 2. High output for 5.7 liters. The quality is worth the fuel bill, at least at 2.50 a gallon.