gas guage says losing gas quickly (guage is correct...now a mileage problem)

[cobradcab6]

filled up with gas today and then came home, left again an hour later and the gas guage says i'm already halfway between full and three quarters. it does move some as i drive depending on if the truck is level, which is normal. but it seems to move a little extra or maybe i'm noticing it more since i'm worried i'm losing gas some how. there isn't any evidence of a leak under the truck or around the tank, and i don't smell any gas in the area, but the guage now reads just above three quarters so its definitely dropped more than just the normal movement from being unlevel. is there a way to tell if my float is stuck? what else could be wrong? any and all suggestions much appreciated. wanna get this figured out asap, not rich enough to afford to be losing gas :yikes:

[YotaFun]

Odd quwstion, bust did you install any aftermarket lights laltly?

I had the same problem, dude to a losse ground somewhere, every time I turned off my lights my gas gauge would drop.

Just a thought.

[Seanz0rz]

the last 6 months or so ive noticed if i pull the filler nozzle out when it first clicks off, im not actually full. i let it drain into the tank and then click it again till it stops, this usually gets me to full. just an idea to throw out there.

[cobradcab6]

i haven't installed anything, but i may have some wiring still ran from lights in uninstalled so i'll check to see if anything is funky there.

as far as filling the tank, i filled a bit more after the first click, didn't take much to round to the next dollar which is what i usually do. I'm going to run it today and tomorrow and try to fill up again tomorrow and see if the tank holds as much as the gauge says it should. that way i'll know if its the gauge that's messed up or if i'm really losing gas some how.

[YotaFun]

the last 6 months or so ive noticed if i pull the filler nozzle out when it first clicks off, im not actually full. i let it drain into the tank and then click it again till it stops, this usually gets me to full. just an idea to throw out there.


Mine has been doing that for the past year.
Its really freakin annoying.
Stepdads 02 doesn't do it.
How I envy that runner more and more...

[corax]

get a locking gas cap . . .

[Tankota]

get a locking gas cap . . .


Haha, yea. Its probably the kid across the street steeling gas for his go-cart.

[cobradcab6]

haha........ kid must be hiding in the bed of the truck and stealing it while i'm driving then

[04 Rocko Taco]

Try running it until its about to run out of gas, fill up, should be VERY close to 18.5 gallons. If that works, reset the trip odo, and drive around till about half a tank or so (better if you could do it contiusously, but I know nobody likes to waste gas (but this was we can rule out the stolen gas route) then go back, and fill it up again, and divide the number of miles you drove by the amount of gas your truck to fill up, and see if it seems right. If so, I would just keep a close eye on that gauge, if not.... then come back. :)

[Good Times]

Once you sort out the fuel consumption figures look into the fuel sender unit. It might just be going bad. All you need to do is pull it off and just run an ohm meter test on it. Check your high and low settings in your FSM (Field Service Manual) to determine if the high/low numbers are hitting on the ohm meter. If it does not then you know what you need to replace. If not, I'm not sure.

My bet is that your fuel sender unit has gone bad.

[RunnerUp]

Try running it until its about to run out of gas, fill up, should be VERY close to 18.5 gallons.

no matter how close to E i get i have NEVER filled up more than 17.5 gallons... even the time i ran my truck clear out of gas it didnt fill up to 18.5, does yours? is mine really that dented?

[YotaFun]

Try running it until its about to run out of gas, fill up, should be VERY close to 18.5 gallons.

no matter how close to E i get i have NEVER filled up more than 17.5 gallons... even the time i ran my truck clear out of gas it didnt fill up to 18.5, does yours? is mine really that dented?


Probably.
I about coasted a few weeks ago into the station and it was 18 for me
(i have a slight dent too...)

[cobradcab6]

ok so i filled up with gas when the gauge said i had 3/4 of a tank...... that would mean it should take about 4.5 gallons if the gauge was correct. i had only driven about 40 miles so it should have only taken just over 2 gallons to fill up. well it took about 4.5 gallons so that means my gauge is fine and something else is causing my gas mileage to go from 17 down to about 9. so now the hunt is on to find out why my mileage would be cut in half all of a sudden.

[Tankota]

Wow that pretty drastic. Does it still have all the power you think it should have.

I wonder if it could be a fuel leak. The hard thing about gasoline leaks is that they usually evaporate before you can find it.

[cobradcab6]

yeah everything i've checked around the tank and the fill hose all look sealed and dry so i don't see or smell any signs of a leak. i haven't noticed any power loss either, just the mpg

[04 Rocko Taco]

If there is NO power loss, then that in itself almost points to a leak somewhere, just about anything that will cause your mileage to vut that drastically also would cut power drastically.

As far as not finding any leaks though.... a few other easy things to check...
fuel filter? (also a known place for leaks)
plugs/wires?
coils?
tire pressure? (although this would have to be WAY off I can run with 35 psi, or 9 psi, and still be within 4-5 mpg)

[bamachem]

let me take a wild guess... 120k to 140k miles, probably a 00/01?

correct?

rear O2 sensor would be my guess. i had one going south and was getting 13MPG with no check engine light. replaced it w/ a bosch from URD and MPG's jumped back up to 18 or so. you can check it before you drop $100 on a new one too...

[cobradcab6]

2003....... and not past 100k yet

[04 Rocko Taco]

I did have a convo with Jesse about the O2's Andy. Sounds like it may be the culprit. Link to the testing procedures? I am going to help replace if it seems bad.

[bamachem]

there's a procedure in the FSM - which i don't have in front of me.

make sure to get the replacement from URD, and if you do, then one phone call to them would give you the tech help you'd need to diagnose a bad one too...

[4runnerchevy]

Here is a good O2 test procedure.

http://www.ttora.com/wiki/index.php/Oxygen_Sensor_Test

[cobradcab6]

thanks!

[04 Rocko Taco]

Print that out and show up on saturday.... We'll do it on Sunday if you do.