Engine/Transmission (1998.5 - 2002) Only getting 15-16mpg .

[LLewandowski]

So ive owned my truck for just over a month now . The highest mpg I could get it up to was 17. 1 , thats totaling babying it keeping 60mph and under . Normal driving is about 15. 5 . It has 75K miles on it .



It says this on the overhead , but every tank load I do it by hand and the overhead is right on . It is cold here in NY and I know winter fuel has an influence .



Not sure what my rear end is , can someone tell me where to find this info?



On a side not I know I should get a fuel pressure gauge , can someone recomend what one to get?



thx guys .

 

[rwitt]

Welcome to the TDR! You need to add your truck signature so that we can see the type of truck you have. As you can see by my signature at the bottom you can tell basically what I'm driving. There are a lot of variables to MPG(gear ratio,transmission, SRW,DRW,2wd,4wd, etc. ) but winter fuel will have an effect on your mileage. On the rear differential cover there should be a tag which will give you the gear ratio for your truck and I also believe there's a sticker either under the hood or in the glove box that gives the options for your truck. Fuel pressure gauges are a must for these trucks (24 valves) and you can purchase them from Geno's Garage or any reputable diesel shop in your area.

Rich

 

[Nate]

Sounds like normal fuel mileage to me. I get about 16mpg average.

 

[Regcabguy]

Fuel Mileage

Sounds like normal fuel mileage to me. I get about 16mpg average.

I'm envious of the guys on this site that realize high mpg but I'm not one of them. I average 13mpg with my popup and maybe 15. 5 or 16 without it. Highest ever was trip to Phoenix area from San Diego:19. 5@ average 70 mph and a tailwind,empty.

 

[WestTN]

I average about 21. 5, but I winter in Florida, so no winter fuel or cold weather. I doubt the mileage difference between 3. 54 or 4. 11 gears would be very signifcant as they aren't that far apart. Do you idle the truck very much? I have never bothered with that. Even when towing it's start it and drive it away. Mine is idled only to cool the turbo.



Some have stated that cleaning the MAP sensor has improved mileage. I've never tried that so I can't comment.

 

[Nate]

I pulled mine out a few months ago and it barely had a "dust" film on it.

 

[RAJohnson]

You guys might try cleaning the IAT sensor. It will have more to do with bad milage. I get 13-16 pulling depending on the weight. 18-21 empty depending on the foot :-laf :-laf :-laf

 

[Jetpilot]

I I doubt the mileage difference between 3. 54 or 4. 11 gears would be very signifcant as they aren't that far apart.

In our truck it is around 3-4 mpg @ 70 mph.

 

[LLewandowski]

Ok thanks guys . I just wanted to make sure since I see alot of people claiming over 20mpg . Maybe in the summer .



I do let it idel and warm up alot , but when I got the 17ish mpg I din't purposly just to check .

 

[EGaskamp]

I get about 13 with no load. The best I've ever gotten, and I was babying it, was 14mpg. And that was with the stock injectors. Idon't know what is up with my truck. I let my buddy borrow my stage 4 JR's in his 2wd reg cab dually 6spd and he got 27mpg!! No joke! With his stock injectors he only got 16-17mpg. I'm stummped!



Eric

 

[terrywerm]

Don't forget that tire size and tread design will have a big effect on mileage as well. That seems to have been the biggest factor in what I've been seeing for mileage differences. When I had 285/75R-16 with mud tread I only got about 13 or so during the winter. Now I'm running 265's in more of a highway tread and am getting 18 even during the real cold weather, and it goes up to 21 to 22 during the summer.



I'm in Minnesota so I experience the winter fuel problem here, but have been getting 18 to 19 during the winter months. My idle time also goes up somewhat during the winter, though not what seems like alot. Idle time adds up fast though!

 

[JKinney]

My last tank was 14. 1 hand calculated 1/3 of the mileage with smarty 0n #8 1/3 with smarty on #9 1/3 with smarty back on #8 but hauling fire wood commercially in my dump trailer.

 

[Ereynolds72]

I've gotten 15pmg since I've owned it. I've now got 101,500 miles on the truck and it's been pretty consistent. I've got 4. 10s and most of my driving is above 65mph. I never put a boost gauge on it but will the higher rpms keep boost pressures high? When I'm at 75mph, I'm turning about 2,375rpms.

 

[LLewandowski]

does anyone have any info as to where these sensors are located and what to clean them with?

 

[RAJohnson]

does anyone have any info as to where these sensors are located and what to clean them with?

Yep here is a link to show where there located: http://dodgeram.org/tech/dsl/mt_2_feb98/fuel_sys_comp.htm



Remove and clean with carb cleaner. If you do a search on IAT you will find the factory specs for it as well if your in to bench testing and calibrations.