Engine/Transmission (1994 - 1998) 20 miles per gallon

[Neibe]

I found out how to get 20 miles per gallon I followed my mother in law from Iowa to Missouri and was forced to go the speed limit and guess what I got 20 miles per gallon. Go Figure!

 

[Shrimpy]

Good God man... ... ... ... . A regular purgatory on earth. I would possibly fall asleep following mine. My mom on the other hand... ... ... ... ... ... ..... get OUT of the way.



Jim

 

[JohnE]

I get 25 mpg driving 80 mph. 2wd does have advantages

 

[Jeff H]

At 80mph John. I think they consider that fly low.

All around driving

21 summer

19 winter

Thats with 32 inch tires. A 5spd manual & 4x4.

The 370 injectors didn't even change my mileage any.

 

[Got Smoke?]

I love my 3. 55 gears! :-laf



I just recently aquired a new Club Cab truck. 3. 55's are a MUST have because I rarely tow, and mileage is a main concern of mine.



On the way home with my new-to-me truck I drove 211 miles before topping the tank back off to check my milage..... I hand calculated 23 mpg. I think it was a little high, but I'm only running 255/85 tires and my cruise was set between 70 & 75 the whole way.



Got to playing around with the AFC the next day and all last week my milage SUCKED!:{ Picked Piers brain about it this weekend @ TiM because he's "the man. " Well I said "all I did was put in a boost elbow and pull the rackstop, but I didn't show boat all week and my mileage still suffered" ... . without hesitation the man looks at me and says where's you AFC housing at? I had completely forgot I moved it full forward when I reinstalled the housing. Before leaving TiM I moved it full back and guess what... . my mileage came back to me on the way home! Oo. Oo.

 

[cArNiVaLwOrKeR]

@75 i get 19. 9 then of course the slower the better???

 

[OaborbaG]

at about 75mph i get around 22 or so, it went wayyyyyyy up when i installed the transmission, the lockup helps milage a lot

 

[Cooker]

Originally posted by Got Smoke?

without hesitation the man looks at me and says where's you AFC housing at? I had completely forgot I moved it full forward when I reinstalled the housing. Before leaving TiM I moved it full back and guess what... . my mileage came back to me on the way home! Oo. Oo.

So on your truck the position of the AFC housing did impact your mileage.



I brought this up once before and it seemed to be a moot point by the replies in the thread but I can remember a long time back Ted J. said that the farther forward the AFC the less fuel economy, which seems perfectly logical to me. It would seem then that with a valet switch, and therefore no rack travel, that mileage would increase as well, but again when I brought this up before it seemed to be a moot point.



I guess every truck is different. I'm glad on your ride moving the AFC back a bit did give your some of your mileage back. I wish it worked on mine

 

[CumminsPower98]

This is interesting. Mine is full forward and has been for a long time. I have the medium spring adjusted as per instructions for my elevation. I still get good mileage. I generally get 20. 5 to 22 town driving in the summer. My all time high is 23. 6 driving 70 much of the time. My cousin's '97 was getting real bad mileage and he just recently tightened up the AFC spring and the mileage came way up. I think his housing is full forward also. I might have to play with this some and see if I can improve what I get a little. What I don't understand is the relationship of moving the housing to the spring adjustment.

 

[Lsfarm]

How to get high fuel mileage

Go to your doctor, get a 'scrpt for Valium, take two [double dose] prior to any lengthy trip. Just cruise along in 'never-ever land' at about 60 mph. You will get excellent fuel mileage.



It helps to drive on continious downhill trips, and make sure Mother Nature gives you good 20 mph tailwind too! And of course find a 18-wheeler who doesn't mind you being 10 feet behind drafting his trailer.



THEN you can have one of these 'bragging rights' fuel mileage numbers!!



Hey, even with my 'lead foot' I can get 22 mpg if I follow Steve StLaurent towing his 35' travel trailer to Muncie!! The tailwind helped to.



Our Cummins' engines net us some of the best fuel mileage available in a pickup, no doubt. But I have had six of these rigs new from the factory since '96, and currently own and drive two, one '01, and a '98 12v, and with several different drivers trying to get mileage, NONE of my trucks has EVER netted me over 22 mpg, even under extraordinary weather and driving conditions. [like described above minus the Valium]



I would suggest that a two month long mileage check is much more realistic, so that the one underfilled tank that nets a wonderful 'mileage' number doesn't become the 'bragging rights number'



My '01 gets 18-19 on a normal 70 mph 300 mile trip with normal weather and no underfilling, and my '98 does the same. Both are 4x4's in good health. Around town 16-17 is a good tank, often it is less. If I drive normally and cruise at 75-85 then I'm in the 16 mpg range.



Greg L. From reality check land

 

[Got Smoke?]

Originally posted by Cooker

So on your truck the position of the AFC housing did impact your mileage.

Yes, that was the only change I made before leaving TiM and I noticed a SIGNIFICANT change in my mileage on my way home (36X miles to TN). I imagine I would get even a little more if I put my rack stop back in, but the whole way home I didn't "use any smoke" so I imagine it didn't hurt anything?

 

[RussW1911]

I'm with greg

18-19 on a standard road trip at about 70-75

16-17 in town and obviously lower when the black smoke is pouring out the back... .

 

[nixonbe]

My 98 4x4 auto is only getting about 13 around town and I get about 16-17 running the roads at about 65-70 (around 2000 RPM).



Is this normal or is there something wrong? I noticed that someone mentioned that after installing a new trans. there milage went way up. I do feel like my trans is not performing up to par. It seems to slip a little from 2-3 and sometime will not downshift or unlock the converter?



Just wondering. thanks for the feedback.



Brandon

 

[rsaderlund]

Brandon, my truck gets the same as yours. The only difference is mine is blowing black smoke on the ricers and eating up the big 305/70/16's

But I can get 17-18 in town if my right foot was a tad lighter!

 

[Cooker]

Originally posted by nixonbe

I noticed that someone mentioned that after installing a new trans. there milage went way up.

A more efficient trans may help around town mileage but will do nothing for the highway MPG's, unless your's is slipping while locked up and cruising and if so you have a huge problem which is not likely.



FWIW - With the cruise set at 68 MPH my fathers stock 1998, QC, 4x4 with 3. 55 gears will get 23+ MPG. He has done this on more than one occassion. When I drive his truck the best I can get with it is just shy of 21 MPGs. MPG's on my truck are a different story

 

[Cooker]

Originally posted by Got Smoke?

Yes, that was the only change I made before leaving TiM and I noticed a SIGNIFICANT change in my mileage on my way home (36X miles to TN). I imagine I would get even a little more if I put my rack stop back in, but the whole way home I didn't "use any smoke" so I imagine it didn't hurt anything?

Thanks for the reply. I was hoping if I drove mine in Valet (with no rack travel) I would net better MPGs. I have only done one extended trip since I installed the valet and MPGs seemed the same. Around town I am usually towing a trailer so it is hard to get and accurate determination of changes in MPGs. Maybe after a little more tweaking I can increase my highway MPGs with the valet on

 

[JohnE]

Re: How to get high fuel mileage

Originally posted by Lsfarm

...

I would suggest that a two month long mileage check is much more realistic, so that the one underfilled tank that nets a wonderful 'mileage' number doesn't become the 'bragging rights number'

...

Greg L. From reality check land

My mileage is based on long and repeated trips on the same freeway. I have highs of 26+ mpg on short fills.

My economy neared gasser levels when the head gasket failed.

As I wrote, 2wd does have advantages.

 

[BigPapa]

I've had my truck now for three years and I check mileage on every tank (my fuel guage isn't working so I have to keep up with milage). I fill up at the same pump unless I'm on a long trip.

Running empty in summer I get 20-22 mpg and winter 19-21. On four trips of over 600 miles, running empty, I've averaged 26 mpg generally running @75 mph with the cruise.

 

[gds3076]

My 96 12v gets 20 mpg whether I do 65 or 70 and I have 4:10's. I have driven like a grandma to see if my milage would go up and it didn't. My fuel gage is broken as well. So I have to constantly check my milage. 200 miles and my truck only takes 10 gallons of fuel. May be someday I will fix my sending unit...



Greg

 

[I-6DZL]

I also have a 96 12v 4:10's, I've gotten no worse than 18 mpg, and no better than 20. 5, but i usually run 75 no matter what. While following Greg L back from Muncie this past weekend i got 25 to 26 mpg from the un-used fuel he was putting through my air filter And that was driving up-hill ( you know going from Indiana to Michigan ) LOL