I have a 05 ultrasport and everytime i fill up my tank my estimator calculates 445+ but i only get about 200 miles per tank... is there something wrong with my car or is this normal?

 

the top most factor in gas mileage is driving habits. if you consider yourself a sensible driver, then you can start looking at things wrong with the vehicle. do a complete tune up, plugs, fuel filter, even a 3 point Sea Foam job. see if that boosts your mileage.

 

The faster you go the faster you empty your tank...

 

yep, its all on the way you drive. i know its tempting to accelarate hard from a stoplight or all the way to the stoplight and then slam the brakes, but that will kill your mileage.
Try to coast a lot in neutral- like when you see a red light half a mile away, just slip the car into neutral and coast . if the light changes, you can put it into the appropriate gear and roll on.

 

Check your tires. Rolling resistance is a HUGE factor in fuel efficiency

 

Must be rolling on 4 flat tires with that big a drop in mileage. Hmmm looking at approx.13mpg if the numbers are accurate.
Low air can effect around 3-5% drop in mpg

 

Check your primary O2 Sensor

 

Is your airbox stock? do u have any aftermarket filters in it? Also, might be your MAF sensor, if it gets dirty, mpg go down.