Should My mpg's be soo low

[park233]

Ok, Im just a dumb, punk ass kid and might drive like it once or twice but My 90 325i did like 30 miles to a quarter of a tank..I drove reasonable the whole time..but it seems to be getting worse and worse..Ive changed the air-filter and oil and belts and see no leaks but not much else... What could be causing this and is it fixable or is there any thing i can do to help, Its eating all my money as quick as i can make it. Please help! I really dont wanna sell it because i cant afford to drive it. Its too much fun :o

[flying_violin]

The gas gauges can be finicky sometimes. Mine will creep up and down by as much as an 1/8th tank as I drive. A better way to find out your mileage would be to record your mileage at each fill-up and to do the quick calculation yourself. I have a 318is, but I get around 30-33 mpg. And yes, I feel the need to rev it to 6k every once in a while too!

[Jafxod]

if the odometer works find out what a full tank of gas gets you, the gauges in these cars suck.

[dreamer420]

my gas gauge when it gets to a quarter tank, if I drive it hard I can watch the gauge go all the way down to empty, then if I start driving softer, it will go back up. if I park at an angle with the nose of the car higher, the gauge will go to empty, and will go above a quarter parked at the opposite angle.
have you actually run out of gas and stalled out? if not then your gauge is probably just finicky like most E30's.
my gauge will actually go much past the empty mark, and I have not run out of gas while driving ever. just drive it till your gas light comes on, if it works, if it doesnt then drive till you run out of gas to see where it actually runs out. keep a gallon in a jerry can when you do this so you dont get stranded.

[TurboJake]

Mine reads in the red when I have about 12 liters left in the tank (According to my OBC). I just wait until my light comes on. Never ran out of gas yet.

(I don't like that my gauge is off though. This has only recently developed over the last couple months, along with the infamous temp gauge waving like a hyper 2 year old.. Must reflow solder)

[Threehz]

I'd say trying to figure out gas mileage by gauge will at best give you at least 20% error. I calculate my gas mileage every time I fill my car up so I can see if there is ever any fluctuations, which would mean something is wrong, not to mention it's good to know.

Next time you fill up, fill your tank all the way up.

Reset your trip to 0 and then don't touch it till next time you fill up.

Now keep in mind the more miles you drive before calculating the more accurate of an average MPG you will get.

So next time you want to fill up, fill it all the way up again. Write down how many gallons you put in (This will be exactly how many you used since filling it up last time) then divide the number of miles driven (on your tripometer) by how many gallons used.

After that of course, reset your trip again so next time you fill up you can calculate again.

This will give you the least amount of error. Hope you find out that your car isn't guzzling!

[TimKninja]

Does the car get up to normal operating
Temperature? If it stays in the blue, your stuck in cold start enrichment.

Your 02 sensor could be bad.

You could have a Vacuum leak. Does the car have. A smooth idle?

[Nsquared97]

I'm assuming you don't have an OBC that gives you an average MPG readout do you?

[park233]

My tac with the mpg thing dosnt work..I have no idea why but i think i have found a source of the problem.. maybe and found a few new problems, The O2 sensor seems to not put off any voltage at operating temp. It does get up to op. temp... And It seems like my oil smells like gas, It was changed in the past few hundred miles too... Is it blow by or is there somthin else...Maybe vacuum system?

[DuMa]

do a tune up
remove unneccessary weight