Adam2001WS6

iTrader: (1)

When does the Check Gages light come on the dash? When does the Fuel light come on? I guess that would be my answer, because when I'm trying to figure this stuff out, I normally try to run the tank down as low as possible. So I guess you are right, 99345hp, I need to use a gallon or 2 less than 15.5.

I'm gonna do this 2 or 3 times and I'll get back on and post some more accurate numbers.

99345hp

I know in my dads 2000 gmc 2500 when the low gas light came on it still had like 5 gallons left in it.

Fill the tank up till it clicks, reset trip meter, drive it till there is about a quarter left, then fill it up till the click. check the amount of gas you put in the car.

Take the miles driven since your first fillup and divide it by the gallons on the pump.

Adam2001WS6

iTrader: (1)

Alright, will do.

98cherrySS

iTrader: (2)

Hey hey! Go Steelers! - I couldn't help it.

02 sensors can have a serious effect on gas mileage. I'd swap both upstream units as they help determine fuel mixture.

JD_AMG

You need to fill the tank up all the way (until the gas nozzle stops itself), reset your trip mileage, and then drive.
Then next time you fill up, fill the gas tank all the way like before, and see how many gallons the you put in the tank according to the pump. Then take THAT number and divide by your current miles.
Also put it in 6th gear as soon as possible.
Last time I checked my gas mileage I was averaging 21mpg mixed city (30mph or lower with traffic) and highway (50mph+), and a good amount of romping over the weekend. If I drove it normal Im sure I would average at least 25mpg.

Adam2001WS6

iTrader: (1)

If you are in 6th gear as soon as possible, doesn't this sometimes bog down or lug the engine and actual cost MORE fuel to be consumed. Simply put, isn't it sometimes better to drive at a higher rpm (i.e. 2,000) in say 4th or 5th gear as opposed to a low rpm (i.e. 1,000) in 6th gear?

9000th01ss

iTrader: (10)

I thought the same thing. I took several 2000 mile trips last year and got around 24 mpg. Last trip I took, I drove in 6th and just tried to not accelerate hard and to not downshift and pass someone. I got 27 mpg driving like this on the last two trips. And I have 3.73's.

One other thing about calculating fuel used. It doesn't matter if you run from full to 3/4 and fill up. as long as you take the actual gallons you used (put back in) and miles driven to do the calc it still should come out correct.

SladeX

My highway mileage is amazing, 80mph and I can still hit 26mpg, do 70mph and I can hit 29mpg.

My city on the other hand blows goats. I use up more than DOUBLE the fuel, ie somewhere around 13mpg in city. A few quick blips on the highway and I can toss that up to a combined 18-20mpg.

You also have to take into account your driving in another way in city. How often do you sit idling? How often do you accelerate, ie from stops or from x speed to y speed? Keep in mind the energy used to accelerate a mass from x speed to y speed is enormous compared to the energy used to overcome wind resistance + tire friction of the roads, this is why highway is so fuel efficient. Cut mass of the car or increase aerodynamics, and the mileage goes up on highway far more than the city mileage.

The more time you spend accelerating opposed to holding the same speed will dictate how much fuel you will use when driving. So city driving for one person may be completely different from the next guy who drives in the city but rarely stops or blips throttle.

JD_AMG

As long as your engine is not really bogging (and you can feel it).
Driving at 1000RPMs will yield better gas mileage opposed to higher RPMs. For reference I usually switch to 6th at around 50mph. If you are cruising at a set speed for a while put it in the highest gear possible to be around 1000RPMs.
This isn't some gutless 4 cylinder, we make gobs of torque down low, use it.

Fifedogg

iTrader: (15)

****.. I get 170-200 miles per tank in my 402. I have gotten as much as 360 miles in 1 tank driving to vegas and back at 80 MPH when I had just bolt on's in my 346 ci.

Blackhawk777

I thought that we had bigger tanks than the 15.5 gallon mark?? I'm pretty sure it's closer to 16.5 or so.

RedRallyeZ

iTrader: (20)

250 was about average for me mix of city/highway before H/C, stall, gears. wouldnt call that horrible at all. i have a similar route now that ive got all that stuff and its about 190-200 miles a tank filling up with an eighth or so left in there,

get another daily driver, it helped me out a ton during the summer

yungepjr

iTrader: (1)

thats weird . i got a 00 SS. i used to get hella shitty gas mileage and then realized it was because i was gunnin it from start to finish lol i jus recently filled up and reset my trip meter. i took it easily and the tank lasted me a week and i went 220 miles and still had half a quarter tank

Blackhawk777

Ehh, no matter what the tank size is, I seem to be on par with alot of geared autos. roughly 17-19 mpg combined city/highway.

wht01ws6ta

iTrader: (45)

Around 16.9 I think, my VCM says max capacity is 16.8 gallons. The gauges read empty long before you've used up all of the fuel though, I've never put in 16 gallons even though the gauge was reading below E for a good while.

SladeX

My gauge is horribly inaccurate. Close to half will actually be gone just after aroung 1/8 below the first quarter mark, 3/4-1/4 represents 1/3 of a tank, the last 1/4 will read as a quarter until you are down to your last 2 gallons then it plummets to red line E as you waste out the last bit of fuel.

Adam2001WS6

iTrader: (1)

Manual says 15.5 gallon capacity... why would it be wrong?

wht01ws6ta

iTrader: (45)

To keep you from running out of gas?

wht01ws6ta

iTrader: (45)

I just checked my owner's manual for a 2001 like you appear to have and it says 16.5 US gallons.

Scoggin Dickey

iTrader: (34)

Tank size changed after 98.