06 Megacab with real bad MPG

[TWMiles]

I have a 2006 Megacab (diesel) 2500 4x4 with automatic trans. I am getting around 13 MPG HWY. I pulled a 3,000 pound horse trailer this weekend 600 miles all HWY flat land at 70 MPH and got 9. 4 MPG The truck now has 3,000 miles on it.

The truck is still all stock at this point. Can someone tell me what is wrong with this thing?

 

[MasterChief]

I am not able to tell why your MPG is low, but I will share with you what I am getting.

You can see what I am driving by reading my sig. the best I get on the highway is about 16 to 16 1/2 mpg. Towing my fifth-wheel (every bit of 14K) I get about 11-12mpg. My motor and drive-train are stock (no chip). Notice I have a 4. 10 rear. My brother just bought a 2006 4X4 2500 Q Cab with a 3. 73 rear. He just completed 900 mile trip and averaged 19. 9mpg. From everything I have read the numbers I gave you are very close to the norm.

 

[Simplysmn]

looks to me like maybe speed is the killer of your fuel mpg ? try doing a trip at 60 mph and see what happen's.

 

[BHolm]

70 mph shouldn't be too fast to get some decent milage numbers, but it is right at the threshold where the milage starts to drop. My Mega gets 16-18 mostly running 60-65 mph(limit is 60). I think you mostly need to put some miles on. It is far from broken in at 3000 miles. My '05 QC LB took over 20k to get decent milage and the Mega started out pretty bad (13-14mpg). I did switch to Amsoil in the diffs and t-case as well as Amsoil 5-30 diesel in the engine. Not sure how much the lube change helped but at 25k miles I am now getting 17mpg pretty much all of the time.



Keep working it hard, don't baby it and the engine will break in sooner. I don't think there is really anything "wrong" with your truck.

 

[DeezelDood]

mega cab mileage

First thing I did was start a journal (log) for my new truck. This way I can compute actual cost per mile over a long period. Fuel, filters, oil changes, tire rotation, additives etc . It all goes in the log. I am using Stanadyne PF additive in my fuel. Talking mileage, I was surprised how good it was out of the gate. April this year I drove new stock truck, empty bed, tailgate up, SF Bay to LA and back (850 miles) and got (calculated) 19. 2 mpg. Tire pressure 50 psi front and rear. Changed hwy speed up and down 60-70 mph along the way. Truck had 1500 miles on it at end of trip. Another trip 5 weeks weeks later 65-70 mph, this time with Leer shell, and mileage was 18. 3mpg. This trip the weather was 20 deg hotter, so not sure if it was the shell or the reduced air density. The weight of the shell negates any positive affect on drag, or the shell actually increases drag. The Mega Cab is the most aero-dyanmic of the big three. Most recent trip was SF bay to Applegate Valley in Oregon, 70 mph all the way, side trips over mountian passes, 1300 miles, 18. 5 mpg. Weather was 95-100 deg plus for most of the trip. 7500 miles on truck at end of that trip. I did notice on the overhead that anything over 70 mph seems to have an immediate affect. Speaking of the ovhd computer, mine is about 1 mpg low (17. 5 on computer = 18. 5 calculated). My average combined (1/2 local, 1/2 hwy) calculated mileage for first 8100 miles is 16. 78 mpg. Not bad for 4 tons. Looking forward to expected improvements, but I'll take what I have. I plan on switching to synthetic oil after 15k or so. Just installed Amsoil EAa189 drop in filter (my only mod to date). Best of luck to all.

 

[Cummins Cowboy]

my '06 is a fuel hog too, notice the black soot around the rear quarter and bumper near the tail pipe, my '02 never has done that, I wonder if its the new electronics or what, something tells me the fuel is not burning as well as it did before, or could it be the new low sulfur diesel we are running is making the poor mileage

 

[tgrfan2]

I have a 2006 Megacab (diesel) 2500 4x4 with automatic trans. I am getting around 13 MPG HWY. I pulled a 3,000 pound horse trailer this weekend 600 miles all HWY flat land at 70 MPH and got 9. 4 MPG The truck now has 3,000 miles on it.

The truck is still all stock at this point. Can someone tell me what is wrong with this thing?

My work truck (10K miles) is gradually improving. I am getting better average mileage than I ever got with my 2000 47re 4. 10 unloaded. Last week I had to make two 220 mile trips toward the coast. I ran the cruise on both trips set at 78mph but traffic slowed me down sometimes. With an equipment trailer and a little steel the "load" was about 3500#. I only got 13. 4mpg. The next day truck only which is roughly 8500# I got 17. 2 mpg. Only on one trip did I ever get better mileage than that with the 2000. I followed a load down the I about 200 miles never getting over 60mph and got 18. 5mpg.

 

[jelag]

I pull a large trailer..... the trailer weight is close to 20K all the time. . and I'm doing that with a 04 dually... . and 4:10's... its 11 to 13 following the speed limit... .



To be honest the truck has never seen a full tank of fuel empty so I have no real numbers for it... but the overhead indicator is close. . and when the truck is empty I can see 18-20... . when I drive it with some sense... .



A long time ago I learned using a dyno that wind resistance multipies 4 or 5 times every time you double the speed..... and I've seen that in those states that I'm limited to 55... the truck is on the high side of the economy curve... . and in those states were the limit is 75 the truck is on the very low side of the economy curve... .



Remember these are work trucks... . if you expected 18 pulling a horse or travel trailer that weights something..... it just won't happen... .



Hope that helps. . its not the answer you looking for I'm sure... . but its what we've found with several hundred thousand miles under our belts with dodge trucks...



BTW - we own 4 dodge trucks..... and our cost per mile including maintance is lower by at least 50% over the ford fleet that I got rid of..... and the fords didn't get any better mileage... .

 

[MCummings]

I have a 2006 Megacab (diesel) 2500 4x4 with automatic trans. I am getting around 13 MPG HWY. I pulled a 3,000 pound horse trailer this weekend 600 miles all HWY flat land at 70 MPH and got 9. 4 MPG The truck now has 3,000 miles on it.

The truck is still all stock at this point. Can someone tell me what is wrong with this thing?

Speed is what kills our mileage. We get 21-22MPG in our 4wd 4-door dually 3. 73 auto truck at 62mph with the a/c off. We get 15-16mpg at 72MPH with the a/c on.



Towing we get about 14mpg pulling our 19,000Lbs trailer at 70 and about 11-12mpg pulling it at 75-78mph.



Our truck pulls much better with much less speed loss on the hills at 78MPH than at 65-70mph. Seems the trans "hunts" at 60-70mph, and it holds O. D. better at 71-72+mph.



My $. 02

Merrick

 

[wcjp]

I bought an early 06' Mega. Mileage didn't start to improve until at least 8k miles.

 

[Giachino]

- Check your Tire Pressure

- Drive it hard and clean it out (do this periodically)...

- Tow something heavy for a few hundred miles (the more the better early on, helps it break in faster)

- Be patient and wait until you're over 20k... .



My 06 only has 500 miles on it and i just did a 40 mile round trip tonight... . overhead showed 16. 3 average... . (reset when I got on the hwy)... . and was doing around 70-80mph... . I know the overhead isnt spot on, but it's a reasonable ballpark...

 

[Cummins Thunder]

Damn EPA #@$%!

I think the extra fuel usage has to do with making the catalytic converter work properly.



CJ

 

[BHolm]

Damn EPA #@$%!

I think the extra fuel usage has to do with making the catalytic converter work properly.



CJ

Or could it be the 325hp engine in a 7700lb truck The gear vendors OD is a great idea, sure would be nice to get a taller final drive ratio from the factory again though. Looks like the six speed forces higher cruise rpms than the auto now too. My how things change, now the auto has the better ratios and fuel economy on the highway

 

[Burner]

Gear Vendors is nice but a US Gear wold be even better.

 

[JWaugh]

milage getting worse not better

i got a 2006 q/c 1ton lb with 3. 73 gears, when i got the truck new i was getting 19-21mpg on the highway but now at 5000 miles i have a ticking noise in the engine ( suspect sticking injector, going to take it to the dealer to have it checked out) and the fuel economy has dropped to 17mpg max . also when towing a 9000# 5th wheel milage is around 11mpg. hope i can get better than this or it is not really worth having a 5th wheel. it would be cheaper to get a hotel

 

[TWMiles]

Thanks for all the feed back. I just took the same trip today and the mileage did get better. I got 10. 7 mpg going up with an empty 3500 pound horse trailer and 10. 5 coming back with a 1,400 pound horse in the trailer. I hope it only gets better. I still think that is some really bad mileage. I ran 68 mph the whole way. That put me under 2000 rpm's

Again thanks!

 

[zstroken]

Mcummings what is your rear end ratio?

 

[menorton]

I have a 2006 quad cab 6 speed, The first few days I was getting 17-19mpg city and 18. 5 @ 65 hwy. Now I am getting 12. 7 and dropping intown. All kinds of power and plenty of soot on fender. Now since the rains have started it misses in the morning for first 5 to 10 minutes. With 20k miles on truck it is getting worse. If you lug it it gets bad milage like 9. 7 around town. My 95 with 410 gears gets 15. 5 to 17 in town and 16 to 18 @ 70 on hwy. For a new truck I am not impressed. I have even looked for fuel leaking on the ground.

 

[happenin-dad]

MEGA Cab MPG

I own a 2006 Diesel 3500 MEGA cab 4x4 with 8,000 miles right now and tow a 8,000lb. Travel Trailer.



My experience with gas mileage and what effects my truck is the following.



First, I saw a jump in gas milage after 6-7k in miles. Some have told me to wait till 10-15k before I see the true gas milage of my truck.



Second, I have a 4. 10 rear and this by far has the biggest factor in reduced gas mileage.



Third, I have monitored the mileage enough to see a big difference in gas mileage if you tow @ 60mph or less (as was mentioned in a previous thread). I towed @ 70 mph for a while and returned home from a trip @ 60 mph - go with 60 mph for sure.



Lastly, I do my best to stay light on the pedal in terms of "take off" around city/town.



As in other threads, I have gone to snythetics oils but understand this may effect longevity of the motor rather than noticably measureable MPG.

 

[JDecanter]

I average over 19 combination: get up to 22 staying below 70 and with no headwind. Most people get better mileage after about 10,000 miles. I saw no appreciable difference on my 98, 24 valve from the day it was new. Same for my 06 quad automatic.