I'm testing the waters with this one...

I used to make sure to put as much fuel in my tank as my computer said I had used on the previous tank. Therefore i would always know exactly how much was left. Since the car always over estimates the range by at least 20 miles and stops telling you the range when you get low, this was my way of making sure I didn't run out (as opposed to just getting gas )

All of a sudden within the last few months I can't put as much fuel in as the car says I've used. I'm always at least a quarter to half gallon short. this is even after I try really hard and end up spilling some sometimes (not cool).

My question is, has anyone else ever noticed this? Could my computer be off? Could this be a sign of needing a tune up? Is there even such a thing and needing a tune up my adjusting the computer, much like when you "tune" the PCM, etc? the car has felt pretty sluggish this summer, and I swear I still hear that "ticking" from the engine.

 

lol wtf my comp on my 03 ss tell me i have 2 gallons left when the fuel light comes on and i usually fill up with 1 gallon over the comp usage.

I would try and reset it after a fill up a few times and pay attention to the fuel gauge. but more important if your under warranty take it in make them document the issue

 

hi, i remember seeing something about filling to the top, to get the most in as possible, the copy and paste below is from mike(chibiblacksheep) he has a ton of knowlege when it comes to almost anything about most 5th and up generation monte carlos, this may be your problem, he is on vacation and will be back tomorrow and i'm sure he will hopefully followup on this, but here you go with what ha had to say about filling to get the most in!!

chibiblacksheep07-02-2009 10:02 AM
I grew up always thinking "top off" meant to just add <$5 worth of gas to the car because you drove it down the street.

What do they mean? When the car tells it that there was enough gas, you can't add that extra 52¢? I never do that anyway, because it's bad for your car. I used to do it to make the dollar value even, but I was told that by doing that I ruined my fuel sensor and can harm the filter.

 

I'm not too sure of the question.

It kind of sounds like you are using your computer on the homelink to see how much gas was used?

What's the problem?

Also what Chris (Monte Carlo 3831) posted about what I said, is that when the car clicks you to stop putting gas in (it's full) then STOP putting gas in. You can damage the fuel filter by overfilling the gas tank and cause problems.

 

Mine is off on fuel used and what it says the avg mpg is. The less gas I have the farther off it is. If I let that ugly low fuel light come one, when I fill it, it will take almost two gallons more than the computer says, and it usually has it figured at three or four mpg better than I'm really getting. I go by my fuel gauge

 

my gas tank never sees below 1/2.

 

Not quite that good, I usually fill mine around 1/4. After seeing this post I checked it this morning when I filled up. Computer said 10.8 used put in 12.1 when pump shut off. Computers mpg: 27.3 Actual: 24.7, pretty much what dustybird3 said.

I think the computer is an educated guesstimate, it's interesting but as others said I don't pay too close attention to it.

 

my fuel used is always on the low side. my avg. mpg is always on the high side . my avg speed is on the low side. temp and direction is right on the money. I have had the car 3 1/2 years now and I don't worry about it just fill it up when needed and drive. my low fuel light comes on and I have at least 4 gallons left so that's off a little bit also.

 

Thanks for the replies guys.

I'm trying to see if there is a problem. Basically, when you're on a trip in the middle of nowhere and your low fuel light comes on it's nice to know how much longer you have. to find a gas station. Problem is that the distance to empty disappears. I have always used the amount of fuel used to determine this, and it's always worked great. If my car said I'd used 15.5 gallons, I could put in 15.5 gallons and I knew I really was full. Now though, my car will say its used 15.5 gallons and I can only fit 14.5 or 15 in it.

1) I never know how much I really have left (say I'm in Kansas and there's no gas station for 50 miles, or I'm stuck in rush hour traffic can I make it home).
2) I wonder if there's a problem with my computer, and if so does it translate to a problem with the performance with my car. It hasn't been quite right all summer in the performance area and I wonder if this is all related.
3) It's just nice for your $30k car to work right.

Thanks,