Hey, recently I have been getting unbelievable gas mileage. Not even something that a bad o2 sensor or spark plug could do. By bad I mean I put getting barely 90-100km off 20$ of gas. I think my fuel gauge might be broken, I don't know how to check though. I tried not filling up and it showed the red light, surely it would show it if it was broken?

 

For you to check your needle functionality, I would fill up on gas and see if it goes all the way up past F. If it does, reset your trip counter and monitor how many miles you drive and where the needle is. If it is going down much faster than normal, you could be leaking gas or the gauge may be faulty. Do you smell any kind of gas around the car or coming out of exhaust?

 

This is kinda mean for you car, but you could also try the following:
Fill up all the way to the brim.
Fill up a gas can, put that in the trunk,
start driving untill your car starts to "hickup" - as in you are driving along and suddenly revs drop, pedal goes soft, you loose power for a second and then it goes back to normal. That would mean your tank is more or less empty and your pump is starting to suck in air. That would mean empty tank.
Then measure how far you went.

Alternatively, if you want to be NICE. Fill up to the brim. Drive a set distance, say you know from point A to point B is 100 miles. Drive it. Then once you got that distance, fill up to the brim again. You will then know how much gas went into that trip. Also useful if your odometer might not be working properly.

 

When was the last time you had a tune-up? If its been a while you might as well do it and maybe it will fix the problem. Also check out this link it might help you...http://www.gas-mileage-tips.com/26/g...e-this-winter/

 

I smell gas in the car after I fill up but it goes away after a minute or two.

I'll try the methods posted. Btw forgot to say - my speedometer isn't functioning properly, but the fuel gauge and speedometer are two different things right?

 

WTF? You aren't supposed to smell gas at all. If everything is properly sealed.

 

my sister has a gen 5.5 she just needed a new evap system IDK if gen 4 also have a lot of issues with evap system but she was burning money in fuel costs (lol get it!!)