Why is there is no power when you step on the gas and it is using a lot of fuel

could be a fuel delivery problem have you checked your fuel filter ? sounds like a dirty fuel fiter.

Check with the auto parts store to see what the fuel sensor looks like, It should be accessible and I have seen those go on the smaller chevys like aveo.
Look up on internet replacing gas recirculation sensor on google

REPLACE AIR FILTER.CLEAN FUEL INJECTORS,CHECK TIRE PRESSURE.LOW TIRE PRESSURE WILL CAUSE LOT OF FUEL CONSUMPTION.CITY DRIVING WILL BURN LOT MORE GAS,STOPPING VECHICLE THEN GOING WILL CAUSE MORE GAS BURNING, YOU NEED POWER AND FUEL TO GET VECHICLE IN MOTION,BY IT BEING HOT WEATHER, USING AIR CONDITIONING TO KEEP COOL INSIDE WILL CAUSE MORE FUEL CONSUMPTION.

BAD NEWS FOR YOU,BUT!!!,CAR NEEDS TO BE CHECKED FOR FUEL PRESSURE,ECT,NEEDS TO BE SCANNED,GOOD LUCK

A couple of things come to mind with this vehicle. Is the check engine light on? If it is, that will be the first step into making this repair.2nd thing, you may have a catalytic converter that is failing, causing you to push harder on the gas pedal, thus using more fuel. 3rd thing, your EGR (Exhaust Gas Regulating) valve maybe stuck partially open or in the open position. If its stuck in the open position, it will start to plug the port with carbon, still run and lack a lot of power. If there is more info needed, please feel free to leave me a message. Craig

Take your foot of the gas. Fast starts ie speeding away from stops and starts burns more fuel.
Make sure your air filter is clean to allow proper fuel air mix ratio. If dirty replace it.
Lighten your load.Don't carry around a lot of dead weight in your truck. The heavier the load the more gas used.
Use a 91 or higher octane gas, this gas will burn hotter and give you more power thus again needing to step on the throttle less to create momentum
Try to maintain speed limit. speeding cost more.

You may have a dead spot on your throttle position switch in the "off idle" position. Using a scanner or an ohm meter, check the operation of this sensor. If you don't know how to do this, take it to someone who does.
Charlie

have you checked the fuel filter?

It sounds like a problem with your computer or injection system. the computer controls the amount of fuel put in the cylinders when you step on the gas. But it sounds like your truck's computer is having problems controlling this and when you accelerate hard or are towing and step on the gas, the computer just pumps diesel into the cylinders which causes the rough running(i assume misfiring and what not) and the loss of power. But when your not towing or accelerating hard, you are better controlling the amount of fuel going into the cylinders so there arent any problems. Go back to the dealer and tell them there is a problem with the injection system and it adds too much fuel when you try to get a lot of power out of it.

fuel strauner inside tank