Really bad Highway Mileage ??

[jds535]

I just got this truck and got it going so I don't have a lot of History with it.

That said, I have a 98 extra cab 4X4 with an automatic trans, stock tires. 184K miles on the truck but only 70K on the motor I just put in it.
I ran it back and forth to work this week and recorded the MPG. I got about MPG with mostly town driving.
I just did a 25 mile highway run and got ABOUT 4 mpg. It burned 1/4 of a tank of gas in 25 miles. You could almost watch the gauge go down.

My tranny has overdrive and it works, I did not use AC. It was taching about 2700 rpm's at 70 miles per hr.

Anybody have any ideas?

, jeff

 

[jds535]

Thats supposed to say 20 mpg around town, earlier this week, then 4 mpg on the highway today.

 

[Big Jim M]

I think you need a few rithmatic lessions.. Ther is no way to average your milage except from tank to tank.. "this afternoon" is no way to have any idea at all.
Big JIm

 

[Tony Raine]

how are you calculating MPG?

 

[jds535]

ok, here's my rithmatik.

I Filled the tank to the top on Monday morning, reset the trip meter to 0, drove Mon - Thurs, filled up again and marked the mileage at 180 miles.

So 180 miles divided 9.25 gallons to fill up is 19.45 mfg. Now since I did a little puttering around with the truck this week, flushing and refilling the coolant etc and I left the truck running in my yard for 2 hours or so... I rounded the actual up to what would have been approx 20mpg or so.

After the refill, drove to work on Friday, then drove up to the city. I noticed the gas gauge moved quite a bit on the 10-12 miles of highway on the way up, so on the way back I marked the gauge at 7/8 of a tank. ( my job is about half way to the city )
so, on the way back, I had 7/8 of a tank of gas, drove 25 miles, got home had 5/8 of a tank left. My tank is 18 gallons - so I figured I burned 4.5 gallons.
So the math is 25 miles divided by 4.5 gallons is 5.5 mpg. Still horrible.

Truck still runs good. As I mentioned above taching 2700 rpm is not that excessive.

Any ideas?

Sorry for the long winded explaination but

 

[locovaca]

After the refill, drove to work on Friday, then drove up to the city. I noticed the gas gauge moved quite a bit on the 10-12 miles of highway on the way up, so on the way back I marked the gauge at 7/8 of a tank. ( my job is about half way to the city )
so, on the way back, I had 7/8 of a tank of gas, drove 25 miles, got home had 5/8 of a tank left. My tank is 18 gallons - so I figured I burned 4.5 gallons.
So the math is 25 miles divided by 4.5 gallons is 5.5 mpg. Still horrible.

No, you can't do this. Do not assume the gauge is linear. Do not assume anything about the gas gauge, really. The only thing you can use to accurately calculate MPG is your odometer and the receipt from the gas station.

 

[Big Jim M]

Thought so! See above post! Go fill it up again to see actual milage..
Big Jim

 

[jds535]

mouse nest in airbox. The filter was half blocked.

 

[snoman6115]

that happened to me twice. once mouse nest, second time chipmunk filled it with seed. therefore i put some window screen on the inside of it held in place by some caulk and gorrilla tape and hasne happened in over a year

 

[Tony Raine]

No, you can't do this. Do not assume the gauge is linear. Do not assume anything about the gas gauge, really. The only thing you can use to accurately calculate MPG is your odometer and the receipt from the gas station.

ditto. a full tank fills higher than the gauge reads as "full". thats why it seems like the gauge moves faster between 1/2 and E than from F to 1/2

 

[Buba Ganushe]

I run about the same rpm wise to keep it steady at about 70-75 hard to tell for me cuz my speedo is a lil off but then again i do have 2wd