upersleder

i recently purchased a 2002 quad cab long box diesel 4WD, 3.55 gears, and am only getting 8 MPG city and around 15MPG highway. what gives? was expecting lots more! i am wondering if there is anything i can do, since the dealer told me they are not rated, so tough luck! the highway miles were with the cruise on around 60 MPH. i did get a superchips tuner to change the tire size, and i get more along the lines of what i think i should get stock for mileage, with the power upgrade. but was wondering if i need to do something. i have changed the fuel filter.

geer

Mine did that took it to the dealer and they did a reflash. It helped I still only get 14 or 15.

Mopar1973man

Well I happen to have the 02 CTD as well and getting 20.6 MPG. The whole trick to getting the MPG up. Keep you foot out of it. Reduce your wind drag. Keep the loads down. Keep you tires inflated properly.

Adding bigger tire is like reducing you gear ratio! It will make the truck work harder too! So now you gear ratio could be as low as 3.0:1 !!!

I put a topper on mine to help with wind drag (not much but it does!). Also the loads... Mine on the scale is 7,900# so it heavy from the get go! Try not to keep a bunch of stuff in the bed of the truck! (I'm guilty of this at times and it shows on the MPG)

someone here found a article from Cummins about MPG and how to improve it. It was a PDF file... Someone chime in...

CJ

How much bigger are your tires over stock? My truck appears to be pretty close to yours, my tires are stock size. When running empty and at the speed limit I have been getting around 20-21. I dont have a trip computer I just do the math so I dont know how accurate that is.

CJ

upersleder

now have 265/75/16s, the others were 255/85/16.

Mopar1973man

Something is wrong...

235/85 R16 = 31 Inch tire!
265/75 R16 = 31 Inch tire!

Trust me on this one... I had 235/85 R16 and the front and 265/75 R16 on the rear and the transfer case was happy with it...

So a 255/85 R16 is a bit bigger than a 31 Inch tire then drop to a 265/75 R16 is smaller but wider in the face of the tread.

But it is a stock tire size (265/75 R16) for a 02 dodge...

upersleder

that is why i put them on. my question is should i try to adjust the valves, tinker with something else, or do they just very like that? i know we can go down and buy two equal snowmobiles and one will be a bit more powerful than the other, just wondering if there are "good" and "bad" CTSs also? i went as far as to measure the stock tires on my friends truck, which were the correct size, but smaller in dia. either way, i am close in tire size now, so i think i should be getting 22 or so without the tuner. if i were i would be happy.

mishkaya

Hello
Just to add my two cents, I bought my 02 back in March and was terribly disappointed to only get around 15mpg with it. The truck was totally stock and had been meticulously maintained by the original owner. The truck however had less than 6000 miles on it. Since then I have put about 10000 miles on the truck and the mileage has been steadily improving to now around 18 mpg. I am hoping this will continue until I reach about 20mpg.
Mishkaya

CJ

mishkaya, I started out getting 17ish when I bought the truck new. The mpg has steadily improved
since. I just turned 27000 and now getting 20-21, I would expect your milage to increase as you get more
miles on it. CJ

Mopar1973man

Well if it is stock and got low miles then all I can say is style of driving that does it.

* Short trips will decrease MPG - Computer feeds more fuel to a cold engine!
* Heavy On the GO! Pedal will decrease MPG - Self explantory!
* Stop & Go Traffic will decrease MPG - It takes a lot to get the beast to roll!
* Properly Inflated Tires (for 3/4 Ton it should be 45 PSI Front & 40 PSI rear - Light Weight)
* And the list goes on...

As said above I too was getting only about 15 MPG when I bought it (odometer 42) I make long trips all the time 300 - 600 miles. The MPG is great 20 - 21 MPG. But I use the cruise control on the trips. I also try to keep it in the sweet spot RPM's about 1,800 - 2,000 RPM (65 - 70 MPH w/4.10 Gears) will get it on the highway!

When I get home and drive back and forth to town 10 - 15 miles then then MPG will drop for that tank! 15 - 18 MPG!!! Yes... I got a heavy foot! I love to cruise around 65-70 MPH... I pass everything mostly FORD PowerPuke's! I love touching the carpet with my foot... GUILTY!!!!

HOHN

I have a very late-build '02, and it gets 16 city, 20+ hwy if I want it to.

But since I have a lead foot, it usually is more like 16/19-- pretty consistently.

Mileage went up after a good, long, hard tow uphill with high EGT.

justin

phox_mulder

I'm averaging 14 with my late build 2002, hand figured.

Bigger tires, much bigger and much wider, corrected odometer.

I've found if I drive the posted speed limit, I can get the overhead to say I'm getting 20mpg.
Amazing the difference 60-75mph makes (per the overhead),
60mph = 20mpg
70mph = 13mpg
75mpg = 10-11mpg.


phox

roadranger

Some have had luck changing the IAT sensor. (intake air temp)
If it's not working properly, the mileage goes WAY down.
Yours may be in that category...

243

The "only" change I have ever found to increase fuel mileage with two different QC's is to slow down.

On my 99, I averaged 17.5 over 85K miles with and without 275's, a 3-button Edge, several brands and sizes of tires.

I drove 55 on a day trip to see what it would do and got 23+.

Did the same thing with my 01 and got 22+.

Torture yourself and go drive 250 miles one way at 55, check your mileage and return at 75 and check your mileage...trust me though, it's torture

Normally, in town mix is 15.5-16.5 for both trucks.

upersleder

thanks roadranger
thats the sort of answer i was looking for. i also heard i may have to adjust my valves. i have tourchured myself on a trip, it helped a small amount, but not that much, got almost 17. i'm happy with the superchip tuner, i get more MPG in town stompin on the gas now than i used to get on the highway before. but i just wonder what could be wrong, because the 8/15 thing wasnt working.