Gas guage hits empty way faster than it use to

I know our cars dont get the best gas mileage but when i use up 1/4 tank going 25-30 miles in 5/6th gear on the highway thats a little ridiculous. I didnt even hit boost once. I have basic mods 2.93 upper, exhaust, intake thats it. Would a fuel filter be the cause of this? I have been using premium gas 92 octane. I have tried different gasoline types as well to see if it was just some shitty gas that i got, but it has been doing this all the time now.

The other night we were out crusing and i had almost a full tank, couldnt have gone more than 70 miles and the empty light went on. I probably went WOT 1-2 times nothing hard.

No lights are coming on saying I have a problem. My mods are not new and havnt had this issue before. Any suggestions?

70 miles... damn. these cars are thirsty

how many miles do you have...?? have you replaced the fuel filter, PCV yet?

I'd say that if something has changed then something may be wrong with it. My car gets about 22-23 mpg (mostly highway) to and from work. That is about 55 miles one way. Of course that's babying it all the way. I'd suggest measureing the mileage from a full tank a couple of times to get a good idea of what you're getting just cruising on the highway.

I think that is pretty much normal operation for our Gas Gauge, it is non-linear and I've noticed the same thing with mine. Around town from Full to 3/4 I'll get about 70 Miles, from 3/4 to 1/2 about 60 miles, then from 1/2 to 1/4 about 50, and from 1/4 towards Empty about 40. I believe it is just the nature of the beast.

ViciousJay said:

how many miles do you have...?? have you replaced the fuel filter, PCV yet?

Click to expand...

I have ~29,000 miles. I have changed my fuel filter about 8-9 months ago...and it was stored for 4-5 months in the winter.

It seems like once you get to 3/4 full the gauge moves real fast. But I cruise to work at 80 MPH every day for about an 80 mile round trip. Changed the FF 2 months ago.

uhhh,....you sir have a problem.....I got 388 miles on one tank (had an 1/8 of a tank left) on the trip to wilmington I just made. 75-80 MPH 6th gear all the way with intermittent AC use and no boost. your mileage is rediculous.....you should be running so rich your gas should be comming out of your tailpipes! run from a completely full tank.....that info scares me

Whoa, that mileage sucks. You may have a leaky or defective injector(s). Have you noticed any smoke or rich fuel smell when first starting in the AM?
I just got my Cobra last week, and my mileage would not be so bad if I could keep my foot out of the loud pedal!! But so far my mileage is not that bad, maybe 17-18 combined hwy and town, with a good amount of gettin on it.

I checked and I was averaging 15.1 mpg, and that was with my foot in it a lot.

Have you ever cleaned your air filter???
If so how many miles since it was done last..
The fuel filter I do not believe will cause poor fuel economy... just poor WOT (or near WOT) performance..

The gauge is going to be all over the place (as mentioned)...

If you want to know your MPG you have to fill the tank.
Note your miles.
Refill your tank... note your miles again... and do the freaking math!!! :-D

Until you do that you really don't know what you are getting.

Jimmysidecarr said:

Have you ever cleaned your air filter???
If so how many miles since it was done last..
The fuel filter I do not believe will cause poor fuel economy... just poor WOT (or near WOT) performance..

The gauge is going to be all over the place (as mentioned)...

If you want to know your MPG you have to fill the tank.
Note your miles.
Refill your tank... note your miles again... and do the freaking math!!! :-D

Click to expand...

I have 3 different air filters...i just swapped one out for a K&N filter a week ago

I was going to post exactly what Jimmy said. I'll quote him again because it is the only way to check your mileage unless you have a trip computer. You cannot use the gauge only. "If you want to know your MPG you have to fill the tank. Note your miles. Refill your tank... note your miles again... and do the math." Maybe your mileage isn't as bad as you think. Check it again, using the procedure above.

Our fuel tank is 15.7 gallons.....I got 217 to the last tank. That was with city, highway and a bunch of WOT pokes...so that means I got 13.82 mpg. I think thats about average....unless you drive on the highway in 6th gear for 300 miles.

I just filled up on Sunday, and I did some STFT tuning on Monday, and I am just now barely left of the F, and I have 40 miles on this tank so far. I usually see about 110 miles on the first quarter, 175 miles by the half way point, 210 or so by the third quarter, and if I let the low fuel ding come on I am usually sitting at about 255 miles or so. ( I never run her hard with less than three quarters of a tank) This is with very inconsistant and spirited driving. And when I fill up I usually put about 13.5 gallons in if I let it get that low.

Now, if I am hard on it for a full tank of fuel I see maybe 220 miles to the tank at the most, and if I am easy on it I can see as much as 275 miles to the tank.

This is just me recalling from memory. My figures could be a bit off, but the MPG and total miles per tank is correct.

-Jeff

Ok thanks. Going to try this. Its true though when the tank is full the needle stays at the full mark for a while...so that might be the problem...but will test to make sure

Try not to lean on the pedal all the way to the right......

If I am cruising at 75-80mph and no traffic I can get 300+/- Most of the time I get 220-250 on about 13 gallons. I rarely get on it maybe punch it a time or two for a few seconds.

I'm usually at about 225 miles just at or under 1/4 tank. I try to filler up by 1/4 tank.

shit i would be lucky to see 200miles on a tank its more like 160 or so dont get me going when i spray i can blow a half a tank with 5 passes at the track.