Engine/Transmission (1998.5 - 2002) Is 11 mpg out of line?

[LILHauler]

I don't have a truck yet but have been looking at a 2002 TDHO/A4, 4x4 Dually.

The axle is a 4. 10 with the original 235/85r 16's. The truck is just under 60k miles. The factory computer says it was getting 11. 2 in the city and a very short hiway trip netted 11. 4. Every thing is stock on the truck with no after market items. I know of a lot of 12v's that get into the 20's but is the computer on this truck believable? Is the Cummins even broke in at 59000 miles?

Thanks for all your input. There is a TON of great info here.

 

[Mundgyver]

That's pretty poor mileage even for a truck with 4. 10's. I would be very leary about buying it. If you were in the 15 to 16 range then I would be interested, 11's seem low to me though.



There should be someone on the board with a truck like this, than answer better than I can though.

 

[SNiebaum]

Very poor mileage even considering gearing and the weight of a 1 ton dually... then again, the overhead readouts are far from accurate... I easily pull down 15. 5-16 in the city with a lighter truck and 3. 55's... 20 isn't out of the question when I'm highway driving.

 

[bmoeller]

the overhead readouts are far from accurate.

Hand calculated mileage is the best.



I have 4. 10s and a flatbed. Get 13-14mpg. Got better mileage with the dually box. Lost 2mpg with the flatbed.

 

[telliott]

as said before, i would hand calculate mileage before you make any decisions. 11 is pretty bad. Granted, mines not a 1 ton dually, but i do have 4. 10's and i usually get around 16-17 in town.

 

[Bob Cochran]

Mine is a 1 ton dually with 4. 10 and a 6 speed transmission. I can get 11 to 12 MPG at times while pulling my 14,000# 5er. Most of the time towing granted it is less depending on mountains, etc(9 to 10 MPG worst). I average almost 20 MPG and as high as 24 MPG was my best ever. Those all are hand calculated. So I would say 11 MPG is pretty low for a stock truck.

 

[Don Tanklage]

the overhead readouts are far from accurate...

i dont know about these late 90's trucks but my 2000 RT (dakota) is almost dead on. by that i mean within 1/4 mpg, even over 10k miles. is there a gooseneck in the bed of this thing? i would look at it as either the seller is an idiot for towing all over hell n gone and then not resetting it before showing it to you, or he has been staying in town and beating the crud out of the thing. did you look at how many miles showed on the overhead or just the avg mpg??? cuz you did say it went up 2 points on a short hwy drive. if just that short drive changed the avg that much and there are thousands of miles averaged in, then that truck gets excellent mileage...



don

 

[LILHauler]

I found out the original owner from the salesman.
The previous owner confirmed the city milage of 11 mpg. Hiway would net 14mpg unloaded.
When I was test driving the truck, we did reset the computer. The truck was not pulling anything and was loaded with an empty clean box.

Could the milage improve with a few more thousand miles on the motor?

 

[TboneMan]

Given what others are saying about their mileage, I bet the previous owner was one of those people who put the go pedal to the floor whenever he/she accelerated.



I swear by the fact that the right foot has more to do with fuel economy than any other factor.

 

[DCreed]

some 2nd gen owners have complained about poor milage that nothing seems to fix. its on a truck by truck basis. this may be one of those, decide accordingly.

 

[SnoKing]

It is most likely going to need a VP44 sooner than later. Also clean the IAT sensor. Check that it is getting correct boost. Should be 14 to 15 around town and 18 or so on the highway. The TDHO/A4 in your post is a bit confusing. Is it a 6 speed HO, or a four speed auto SO? If it is a 6 speed HO with 4:10, then it is really not a freeway cruiser. The auto's turn a little less RPM's than the 6 speeds in the top gear.



I just got 13. 042 mpg crossing Montana towing a 12K high profile 5th wheel trailer. That was my best ever towing mileage. I put on a new VP44 in the early spring and a PDR35 turbo last winter.



SNOKING

 

[Turbo Tim 1]

Ditto on the IAT, I usually pick up 1-2 MPG when I change mine out. Also have the pressure from the lift pump checked, I had an aquaitence that had a 2000 with a dead lift pump from the factory, he got terrible mileage until they figured it out.



With my truck which is set-up just like the one you are looking at except it is an SO motor, I get 16 mpg in town and on the highway, My lowest tank ever was around 11 MPG and that was plowing snow, allot of snow. My best tank was just over 19 MPG and that was driving 65 MPH or less but mostly on 55 MPH roads. Tell the salesman you want to drive the truck for a week, fill it to the top and then drive and refill so you can hand calculate the mileage.

 

[59Turbo]

I don't have a truck yet but have been looking at a 2002 TDHO/A4, 4x4 Dually.

The axle is a 4. 10 with the original 235/85r 16's. The truck is just under 60k miles. The factory computer says it was getting 11. 2 in the city and a very short hiway trip netted 11. 4. Every thing is stock on the truck with no after market items. I know of a lot of 12v's that get into the 20's but is the computer on this truck believable? Is the Cummins even broke in at 59000 miles?

Thanks for all your input. There is a TON of great info here.

Did you reset the overhead display before getting on the highway? If not you weren't getting true mileage figures. Who knows how long it's been since it was last reset, could be reading an average of 3 or 4 tanks of fuel. Reset it and go back on the highway and recheck it.

 

[LILHauler]

Did you reset the overhead display before getting on the highway? If not you weren't getting true mileage figures. Who knows how long it's been since it was last reset, could be reading an average of 3 or 4 tanks of fuel. Reset it and go back on the highway and recheck it.

Thanks 59TURBO for your advice. We reset the overhead after the hiway trip.
I am new to the Cummins but a Mopar fan for many years. My learning curve on these trucks is ramping up fast.
I just got back to the Blueoval dealer with the truck. The sales manager was strongly advising to put in an offer and no time to inspect the truck further since two others want the truck. Must be a sign that Mopar still rules over the lot full of Super Duties. I put an offer in 1G under the price offered me the day before. I didn't get a call to pick up the truck so I guess someone else will have to work on the fuel milage. I did find out that the lift pump was never changed, so I think it could be suspect.
Thanks for all the great advise. I will have a few more tid-bits of info on the next truck