ok so as most of you know my fuel gauge is stuck on full...so i dont know how much gas i have.

well i filled the truck (26 gallons) monday. since ive done plenum and the whole shabang, ive been gettings 300-325 miles per tank when driving all city. well i did 278 miles of city driving...now i figured i had about 4 gallons...i put 20 bucks in thursday (7.5 gal) so now i figure the truck had 11.5 gallons.

went another 124 miles city driving. now i figure i have about a gallon or so. went to go fill up tonight, and she clicked at $14.39...i was like this cant be right...tried filling it up more, and gas came out the spout a little and it was gurgling.. waited a minute to see if the gugling meant it was clogged and it was slowing going in...nope after about 60 seconds tried again, and gas came out the spout...got under the truck banged on the tank and could def. tell it as full.

so it took another 3.8 gallons....but its full.. i figured (seeing as i thought i had about a gallon) that id have 4.8 gallons with this, and no the tank is full.

So this means im getting like 20-22 mpgs city????? that cant be right....

 

Short calcs like that will always skew your results. Best thing to do is to run full tanks and then calc.

 

i agree with Laramie run it full to empty a few times to see
hows your throttle ? like to you open it up alot..cause if i baby mine i can see 20 our of a tank..although i have a 33 gallon tank..but still

secondly..have you ever had your tank down?

usually the fuel gauge problem is caused by a sending unit

 

yea it is the sending unit....and when i went the 278 miles i thought it was pretty much empty...(seeing is i got about 300-325) and i only added 20 bucks, (7.5 gals) and went 124, so think about it i should have been empty but 3.8 gallons filled it.

i baby it...never goes above 3300 rpms, unless im offroading...just did ALOT of engine work...so maybe it is true...a 95 5.9L with 197K is actually getting 20-22 mpgs city....im excited.

well im going to get a 5 gallon can and have it filled and run it till she runs outof gas so i can get an acurate reading.

 

do you know your gear and axle ratios?

and what all engine work did you do ?

i wouldnt doubt it..if you baby it like you say you do

 

he has 4.10 gears...

 

20 mpgs? I think I should be getting that. Before I did any work to my truck, I was getting 13.5 miles per gallon.
Then I did all the work: Plenum fix with the Hughes AirGap, Summit Shorty Headers, a full tuneup with NGK V-Power Spark Plugs, MSD StreetFire Wire, Mopar Distributor Cap and Rotor, an oil change with full synthetic oil and mopar filter, and a new upstream oxygen sensor. And I got Goodyear SilentArmor tires size 265/75/16.
My gas mileage? 13.5 consistently. And that's driving nicer then I did before all of this work.

Truck runs fine, no codes/engine lights, why didn't my fuel efficiency increase?? By the way, sorry for jacking the thread.

 

your fuel filter..should be in the tank..might be the culprit..i betcha its original

also. a bad o2 sensor or a cat could cause it.

 

what i just did....

port and polished modded kegger intake, with hughes plenum. cleaned TB,
new valve cover gaskets, intake gaskets...EGR delete, Mopar champion copper plugs, MSD 8.5mm wires, Accell dist. cap/rotor, coil, tranny flush, front/rear diff flush, tansfer case flush, cleaned fuel injectors, syn.oil change with mopar filter, have 4.10 gears front and rear with 265/75/16 tires....well i guess its not ALOT, but it cost ALOT...and thats all i did, and the performace is 100x better, but now im getting this much mpgs??? when i first did this stuff (month and a half ago) thats when i started seeing 300-325 miles per tank city, before i was gettng 8-10 mpg. Now all the sudden my fuel mpgs are awesome? is it possible the computer just re-learned everything since theres no more blown plenum and stuff and no more egr? but i reset the pcm after this stuff was done...and havent since, so its weird that it just chaged all the sudden....

 

oh hell yeah..thats a good tune/fix up

i dont doubt it one bit that you broke 20 MPG..plus with 4.10 gears no doubt