Engine/Transmission (1998.5 - 2002) mpg ?

[RHerrmann]

Neen some input on my mpg numbers. I have been reading posts after searching, but want some more ideas. Geting 11. 7 mpg in town lots of stop and go, and not to much idle time. Started driving like old lady and its up to12. 4mpg. 3. 54 gears, auto, 285/75tires. ff good, fp good. Should I clean the sensors? Did have a k&n for about a year. Possible oil coating on IATsensor?

 

[Supermod56]

I would check them, I get better than that towing over 10K at 80 MPH. Around town unloaded I get about 16-17, over 20 on the highway.



Tom



2001. 5 2500 4X4 5-Spd LB QC Black. Catcher ECM, DD Stage-1's, AFE, Bully Dog 4" pipe, ATS Exhaust Manifold, Silencer Ring MIA, JAKE Brake w/shifter switch, Geno's Banjo's, 3 Autometer's on the A-Pillar, Gear Vendor's O/D, Firestone Air Bags, Redline Oil throughout.

Soon-to-have 14cm Turbo Housing and RASP Pump (Thanks Olee!!)

 

[jrhodes]

I get just about 18. 0 in the city and can easliy get 25 to 26 on the highway. Change the fuel filter on a regular basis and keep the air cleaner clean.

 

[Lordsman]

Has it always been like that or a sudden change? I suppose I'd check/clean the IAT, run BK44 through a tank of fuel to clean up pump and injectors, make sure the wastegate wasn't stuck open, and tighten all boost clamps. The winter fuel has been lousy in some stations I've noticed. I get 18-19 around town and 20 highway, and our trucks breathe the same air. I just put on a BHAF, so I'm wondering how that will do.

 

[RHerrmann]

the truck has always gotten this mpg since I bought it used 2 yrs. ago. From reading posts I have seen other people geting 16 mpg or so in the city. all of the filters are clean. and always put diesel klean in at fill up. at $2. 45 a gal. I will be broke in no time. Forgot to mention it does have a shell on the bed. I would not think this would cause such a drop in mpg. Also all boot clamps are tight. filters are clean,tire psi good.

 

[jrhodes]

Just another thought, it might be the oversized tires along with the higher gear ratio. I used to have 285's on my truck but I kept have to step on the pedal too hard to get the thing going. I went down to 265's and things seem to be better as far as acceleration etc...

 

[PeaceKeeper]

I had a 99 2500 short bed that would regularly get 21 - 23 mpg empty, doing 80 - 85 from Texas to Calif. Bought the truck new and drove it 130k and hauled a two car gooseneck along with various types of RVs and the worst I got was 11mpg going over Raton Pass to CO.

I now drive a 2500 sort box 04, have not pulled with it yet, just drive to and from work city traffic and I've never gotten less than 20. 5mpg. The truck now has 41k. Even my 97 F350 PS 4x4 crew cab long box with 4:11 gears got an average 16-17mpg (empty) with 185k when I traded for my current Dodge. One of many reasons I went back to the Cummins engine was because of excellent mileage for the two wheel drive. My only regret is I should have kept the 99 it was a great truck! But with four kids I needed a crew cab!

Anyway I would get the mileage problem checked!!!

 

[RobertMiller1]

I have 285 tires on mine with 3. 54 gears too. Get over 17 city stop and go and 20+ on highway at 70mph.



Did you recalibrate your speedo/odometer when you went with the 33" tires? if you use that extra power... mileage will suffer.



Hypertech and Superchips have a recalibrate function as well as Hp/tq improvements and code reading.

 

[KKohagen]

I have had my truck for 3-4 weeks now. I have 265's and same gears. I get consistenetly 19. 4 to 21. 5 stop and go and 70+ on freeway. I would check the sensors and maybe as previously suggested the speedo calibration. Let us know what you find out

 

[RHerrmann]

it's snowing like mad,might get about a foot or so. will have to wait till next weekend to check out truck. thanks for all the input on this subject.

 

[CTHunter]

mpg

I've got a 98. 5 3500 4X4 w/ 4:10 gears all stock getting 15. 5 mpg in stop and go driving unloaded. I rarely do hwy miles so I got no idea on that.

 

[cArNiVaLwOrKeR]

?

14. 9 all the time

 

[amnewsom]

My 02 sees an uncalibareted - 285s - 18 combo 50/50 city and highway. So I would say better than that if I knew the true rolling mile.



I would double check everything, you list a banks big hoss, I would pull that off and run it for week or so, maybe a tanks worth of unblended summer fuel to get a baseline. Then go from there.



If not, put a block under the skinny pedal.

 

[Makensmoke]

I GOT 19!!!!! On a recent 1000 mile trip down the highway. I couldn't believe it, I think i'm finally getting this ol girl broke in!! My old record was like 14. 7.

 

[RHerrmann]

does anybody have a small monkey I could use to get to the IAT sensor? I sure as heck cant get that sucker. By the time I get my hand in there I cant even move it. changed fuel filter, it was a little dirty, thats surprising its only 4 months old, but picked up 3psi fuel pressure with new filter. disconected boost gauge to check for leaks, its ok. I think I will unhook the big hoss and see if that helps with milage.

 

[DThelen]

I would get rid of the tire's, I had 285's on my truck for a weeks, My milage to a crap and in town ,it made it slow. Don't for get the O dometer is off more with the 285. If the truck come with 245's its off about 15% off. I'm running 265's now and would be running 245's if the truck didn't look like crap with them on there.