Is it 5.4? If not then no it isn't.

Check the list of 2007 e85 compatible vehicles and see if you have a flex-fuel vehicle by default:

Buick 3.9-liter Tarraza
Chevrolet 5.3-liter Avalanche
Chevrolet 5.3-liter Express
Chevrolet 3.5-liter Impala
Chevrolet 3.5-liter Monte Carlo
Chevrolet 5.3-liter Silverado ½ ton 2WD & 4WD
Chevrolet 5.3-liter Suburban
Chevrolet 5.3-liter Tahoe
Chevrolet 3.9-liter Uplander
Chrysler 4.7-liter Aspen
Chrysler 2.7-liter Sebring Sedan
Dodge 2.7-liter Avenger
Dodge 3.3-liter Caravan & Caravan Cargo
Dodge 4.7-liter Dakota
Dodge 4.7-liter Durango
Dodge 3.3-liter Grand Caravan
Dodge 4.7-liter Ram 1500
Ford 4.6-liter Crown Victoria
Ford 5.4-liter F-150
GMC 5.3-liter Savana
GMC 5.3-liter Sierra ½ ton 2WD & 4WD
GMC 5.3-liter Yukon & Yukon XL
Lincoln 4.6-liter Town Car
Jeep 4.7-liter Commander
Jeep 4.7-liter Grand Cherokee
Mercedes 2.5-liter C230 Sedan
Mercury 4.6-liter Grand Marquis
Nissan 5.6-liter Armada
Nissan 5.6-liter Titan
Pontiac 3.9-liter Montana
Saturn 3.9-liter Relay