[Batman]

Tune it! And try bumping the air pressure in your tires! With 2.73's you are probably bogging th emotor down alot if your tire pressure is too low. Also do you have the stock LT4 cam or the LT4 "Hot cam"? I would definately suspect a bad tune if you are just using narrowband O2's, but check all your wires, take a look at your plugs. eliminate something mechanical or electrical before you do anything.