Ok, first I have been geting about 280 miles per tank, I filled my tank up and rest the meter, I am about 85 miles and its almost half a tank gone? I have not been driving it hard either??? Also, I was driving around the mall and I was in first gear going about 9 miles per hour and I let off the gas and my car sounded like a truck slow down with the squeaky brakes and metal rubbing, so I stop and get out to see if I am dragging anything( which I wasnt) , What the hell was that sound??????

 

Did you leave your emergency brake on? It's also possible that you didn't really fill up the tank. Some gas pumps are real sensitive and shut off prematurely. You have to wait a few seconds and pump some more.

 

 

Go out on the highway and reset the MPG setting then drive 60mph for a couple of miles then tell us what your MPG gauge read. If you're getting less than 25, then it might be time to be concerned.

As for your grinding sounds, you might have a stuck brake. That would explain the noise and the lousy gas mileage.

 

It's possible the first half of the tank goes quickly on the fuel guage IE from E to 1/2 = 9 gallons from 1/2 to F = 7 gallons. I haven't experienced this in my Z, but I have in a couple of other cars.

 

Maybe the sound was the other half of the gas tank riding the drive shaft. No, it's highly unlikely the two are connected. Do the test as DavesZ#3 mentioned. Find out if the noise is connected to how you brake, or the clutch, or if in gear or neutral while moving, or occurs when wheels are turned this way or that OR if there is a destroyed wheel chair behind your car.

 

I bet you can't fill up all the way, correct?

 

I have this problem..... my gauge never reads full. Every once in a blue moon it will but only lasts for 2 min. or so... Whats that about?

 

I am able to top off my car and i get from full to empty a minimum of 300 to the tank. If i ride it to the light, i'm usually right around 340 miles. I spend about 40 miles round trip on the highway, the rest is in the city.