I have a 2003 diesel {h.o}with:
4.10 rears , crew cab, 8 foot bed.


This engine was to have better milage than the previous model accrd. to cummins!! My 98 was getting about 14-16 overall.

I have logged nobetter than 10-11 m.p.g driving 70% city and 30% h.way empty!!
I have to the dealer 3 times, the first time the computer was never programmed out of the factory, this should fix it I was told.
Second time in, I was told the valves were out a couple of 1000's?
-This should help I was told , still nothing...........
Is anyone else having this problem?????????


Thanks!!!!!!
Bill

 

Are you going by overhead or pen and paper?? How is your driving style? 4x4? Idle time? Fuel? Fill in your sig.

 

Hi,


Idle time is normal.
Normal driving, nothing crazy.
As far as fig. out the milage, i just take miles driven and divide it by the the gallons needed at fill up.

Thanks

 

okay that is what I was asking. the overhead computers can be out some. With normal driving I think you should be getting better mileage than that. No brake drag?? Tire inflation? Winter fuel? the 4;10 will be a bit less fuel efficient (maybe 1 to 2 mpg I am guessing) 4x4 will eat another 2, cold where you are??

 

Yes, it was a cold winter in Ct this year but it has warmed the last 2 weeks and still......
I was fig. from what I have heard that I should be around 14-17 or so??

 

I'm averaging about 14-16 in mostly city driving with winter fuel. It will drop a couple points w/ the winter blend but yours seems a bit low. How many miles? Mine was pretty low when it was new but once I hit around 12000 miles she broke free....

 

Seems like I remember a thread a long time ago on the same subject. One of the diesel performance shops that advertises here had the problem and narrowed it down to some kind of sensor that wasn't working properly but never registered a code. They just happened to replace it on a hunch and presto, gained like 5 to 7 mpg. They were in the same boat as you, like 10 to 11 mpg. IAT sensor maybe? I dunno. I did a search for you but couldn’t find that thread (may have been a different forum). This diesel performance shop even had an article about it posted on their web site but I don’t remember who it was. Anyway, maybe they will see this and chime in. Good luck.

 

Hi,

My 03 has 10,000 on it.

I spoke to Jannetty rac. and they said either there is a complete computer problem or it can be a map sensor, boost leak?

 

The fact that you have a 4.10 rearend explains a lot of it...

More pulling power, but it cost.....

 

Bill, yeah 10-11 seems to be low. Is it throwing any codes? I'm getting around 16 this winter with mine. As far as boost leaks, have you checked all the clamps to ensure they're tight? Do you fill up at the same place?

I've also read here that many folks have had better mileage from their 2nd gen trucks. But all things being equal, you should see something better than 10-11 empty.

 

Yes, the same place for fuel and there are no codes.
Dealer has to chck for leaks.

 

at 10,000 i was getting 12 mpg...when i hit 12,000 miles she jumped to 16 mpg, .....hang in there its a little eary for concern.

we will NEVER get what the 2nd gens got...mor HP, TORQ= more fuel per mile...which = less MPG.....such is life

 

My truck gets exactly the same as my 2001 HO.

Bill, how much time do you spend warming up in the morning? And do you plug in? If you spend more than a couple minutes warming up every morning that will put a damper on mileage. I never idle more than a minute in the morning unless it's super cold then it gets maybe 2 minutes.

Vaughn

 

I have noticed that my '03 's mileage actually takes a serious hit if I do any interstate driving. it is best around 55mph, and drops quickly above that.

 

My 03 gets about 11-13 in pure city driving, that is lots of stop lights and barely gitting to 45 every now and then. You are in CT right? Where at in CT?
I know that the area where I used to be (Groton) was very hilly and that would make a big difference in mpg.
I have that problem here in Portland now, so I think my milage is OK.
I get about 18-23 on the highway and about 10-13 with my 5VR.