I am posting this for a friend of mine. He bought a 1999 Dodge 2500 2WD with auto transmission. The truck only has 20k orginal miles on it. I am not sure as to what gears he has. He is telling me that it is only getting around 10mpg. Any ideas?

 

Have you seen the truck? Is it a V-10 rather than Cummins? I assume you know it's a Cummins, but at worse my fuel mileage in a QC 4X4 Cummins was 13.5mpg when it was brand new and I was driving in the Sierras with 5 people and a bed overstuffed with camping gear.

 

That truck is just starting to get broken in at 20k =P

 

The truck is indeed a cummins. The owner is older fello and only drives on short tripps.

 

heck my 97 360 got 13 on a good day usually around 10-12 my neighbors dodge v10 gets 14 empty but around 9-10 towing his snowmobiles my uncle gets 11 in his ford v10 empty or loaded. It never changes

 

I can't see how that truck could possibly be that inefficient without a bad leak or raw fuel coming out the tailpipe. I would check the entire intake system for an obstruction or something. That's very little use in seven years. Maybe take that baby out on the highway and open her up a little..

 

I can't see how that truck could possibly be that inefficient without a bad leak or raw fuel coming out the tailpipe. I would check the entire intake system for an obstruction or something. That's very little use in seven years. Maybe take that baby out on the highway and open her up a little..
If he had a grease monkey shop do his oil change, there's a chance the intake is disconnected somewhere..Just guessing..

 

I have a '99 R3500TD with a 6-spd manual, Edge EZ, and other stuff. 17-18 no-load, 10-12 pulling a 4-horse trailer or my '53 drop-deck with 8-ton of hay. I never ran into anyone that got 10 mpg with no-load. I'd say that's abnormal...

 

He never specified whether it was loaded or unloaded. 10 mpg or even less is possible at over 20K GCVWR, but if he is really getting that kind of mileage with an empty truck something is wrong.

 

I still think the truck hasn't been worked enough to properly break in. Doesn't cummins say to wait 20k miles before switching to sythetic to allow for break in?

 

Cummins diesels were not built to take small trips, they were built to pull heavy loads.
The rings probably aren't seated in yet.

 

tell him not to floor it.he might get rod through his hood hehehehe

 

I've got a 2002 HO 4x4 manual trans and I get 14 or so around town. On the road at 65 I'll get around 15 or so, at 55 I get 17, towing my 26' trailer 12 - 13. The best I've ever seen was 18.9 downhill, with a tailwind and a semi pushing.

 

I had a 98.5 that I had a problem with. On the intake manifold down by the IAT sensor there was a 3/4 plug that had worked it self loose and fell out. This will give you no boost and thus pp fuel milage. It might be worth looking at. Just a thought.

Jim

 

The Intake Air Temperature sensor may need cleaning or replacement. Its at the rear of engine on driver side. It requires a 13/16th socket. Remove and clean with carb cleaner and reinstall. If no gains replace. Its about 20$ at the dealership.