Engine/Transmission (1994 - 1998) average mpg?

[DonTX]

There are probably ways to overcome it. The feeling of shutting the drivers door on another rubbery door I don't like. In Mexico the streets used to be lined with them, the Mexicans figured out there was money in upgrading the doors for unhappy owners. From casual glances, it appeared they were just putting on some additional rubber to stop wind whistles and rattles. Somebody with one will probably add some information here.

And I sometimes thought a '98 12v with those extra doors would be so much more convenient. Well they would no doubt, but did not know they rattled and leaked. Sad but now kinda glad until some quadcab 4doorers defend them extra doors. Larry

 

[J.BURCHFIELD]

And I sometimes thought a '98 12v with those extra doors would be so much more convenient. Well they would no doubt, but did not know they rattled and leaked. Sad but now kinda glad until some quadcab 4doorers defend them extra doors. Larry

Mine do not rattle or leak. Maybe the striker plate needs adjusted.

 

[arthr31]

I have a '98 12 valve with the "club cab" style "quad cab". I thought they didn't make the 12-valve with suicide doors? I must have an earlier '98 model. glad i do kinda...

 

[CumminsPower98]

358k miles and no rattles or leaks from the doors. I'm VERY glad for the rear doors on my '98 12v (09/'97).

 

[J.BURCHFIELD]

I have a '98 12 valve with the "club cab" style "quad cab". I thought they didn't make the 12-valve with suicide doors? I must have an earlier '98 model. glad i do kinda...

On a Q-cab the rear doors can not be opened without opening the front door.

 

[ddechris]

My rear doors only rattle if they aren't closed properly. No leaks.



But, there is no comparision when you are putting kids in car seats in the back! I searched long and hard for a 12V QC and I wouldn't trade it, even if the mileage on mine isn't the greatest. It does beat my dad's F150 gasser of the same vintage that's 2k lighter! So I shouldn't complain too loudly.



I talked to the neighbor who manages a truck fleet for a local distribution center. He said the winter blends of ULSD may be a contributor. I told him I didn't think they blended in this area, but he said the cloud point of ULSD is 20 deg F, so they needed to do something. He said they notice a mileage decrease from 6. 0 to 5. 7-5. 8 mpg. He said it doesn't sound like much, but 0. 1 in mpg nationally is a million dollars in the fuel bill.



If the next tank gives me 17 again I'll be happy. If it drops back to 15 even with the filter change I just did, I'm going to 15. 5 deg on the timing. Anybody document any mileage improvement just from timing changes?



- Dave

 

[dpuckett]

One thing I didnt see in 6 pages of posts is the injectors themselves. I have had injectors that were just junk at 130K of light towing and mucho idling with no additives. I've also had them with 300K towing and working hard, popping and spraying just fine. If the 215 injectors arent popping and spraying like they should it will have an adverse effect on MPGs, EGTs and boost.



Daniel

 

[Ahopper]

anyone know what an average price would be to get injectors tested?

 

[Ahopper]

also wanted to follow up on the milage i am getting. scince the trip to mexico ive been getting around 16mpg on highway now. i think my first problem was my bhaf. also i do belive the diesel in mexico got me better millage. (im thinking because they doesnt have any ulsd?) but im wondering if my injectors are hanging open?

 

[arthr31]

dunno about the injectors, but on my second tank of ulsd and mpg has consistenly been 18. 5mpg. That even with insane driving of 100mph or so...



What would cause injectors to hang open? And, would it effect mpg so much?

 

[4570]

Ahopper ,I have a 96 that gets 21 to 22 consitantly on the highway at 70 mph . Your exhaust temp and boost sounds to high compared to mine . My temp runs about 600 at header and my boost is barely noticable unless under a load uphill or heavy wind . Mine is totaly stock except for a 4 inch exhaust and straight through muffler. The exhaust didnt seem to change temp or boost noticably though . Maybe it needs a timing check ? Arnie

 

[SKnapp]

my last tank was 14. 0 ave, no free way. the best i've ever seen was 18. It just doesn't make sense any way you look at it how some people can get over 20. i need to check the actual milage though with the gps, i never relized there was actually a difference when changing tires.

285/75/16 //4:10 auto

 

[J.BURCHFIELD]

my last tank was 14. 0 ave, no free way. the best i've ever seen was 18. It just doesn't make sense any way you look at it how some people can get over 20. i need to check the actual milage though with the gps, i never relized there was actually a difference when changing tires.

285/75/16 //4:10 auto

Getting 20 MPG is for me unusual. Interstate driving during a cool evening without the A/C and using higher quality fuel can get me close to 20. A combination of city and highway driving puts me down to 17 and just under 18. Here in Florida seldom go anywhere without the A/C. I am running 265 tires (inflated to 70 psi) with 3:55 rears (auto) and a Gear Vendor. When on the interstate I set the cruise at 70 (the limit) which puts my RPM at 1500. I would say we both are getting reasonably good milage, all things considered. Our Rams are work horses and they have to be fed.

 

[Forrest]

I've got 3:54s & 235x85s & just did a road trip from Reno to Las Vegas ... 24mpg

 

[SSage]

My 95 3500 dually with a 3. 54 rear gets 19 mpg when driven to work and I don't drive slow. My last fill up was 19. 0 and that was all two lane country roads, my last all 70 mph interstate trip netted 19. 8 mpg. My lowest numbers have been in the 17 mpg range running in the mountains. My highest mpg was 20. 0 when I ran 65 mpg from NC to AL. My mpg went up after I installed the TST #6 and BHAF. The 4" exhaust didn't do much. Towing 11K of trave trailer I got 14 mpg. I haven't checked the milage with the 43' 5th wheel, the fuel gage does drop fast though. :-laf

 

[Kiohio]

This is the 96'

Just got fueled up. 365miles.

235 of it with a 28' GN attached, of that 235, 80 of it was loaded.

40miles (flat ground) with 7k on trailer 40miles (curvy and very hilly) with 5k on trailer.

Mileage 13. 04mpg.

Truck has 285/75/16 Duelers on it. Not sure what that corrects to.

My '89 with 265 70's on it gets 15mpg most days sometimes a little better.



KO

 

[dpuckett]

anyone know what an average price would be to get injectors tested?

Most shops will check them for free if you do the R&R yourself. Labor to R&R shouldnt be more than 2 hours for a 12valve, though.



Daniel

 

[Grizzly]

Filled up at Flying J yesterday, $2. 75/gal. Average mileage around town, stop and go, was 16. 2 mpg. Not too bad for a 4x4 dually.

 

[darom]

I am getting 20-21mpg, 5 spd, 15. 5 timing, 3. 54 rear end. I have a 10 TST plate and 3 gsk that I haven't installed yet.



Should I install the 3 gsk and 10 plate? From reading the posts here, the plate installation didn't affect the gas mileage.



What bugs me most is downshifting from 3 to 2 gear when I rev match the rpms - would a 3 gsk allow for a faster rpm spool up? While accelerating I shift at 2k rpm.



On a side note, this truck gets a cheaper better mpg than my LS1 powered 1998 Camaro (18 mpg on premium gas)!



Thanks!

 

[DonTX]

There are those out there better informed than I, but it is my understanding that the plate nor the 3k spring will make any difference at all - unless you got your foot to the floor and are using the 3g rpms, then it is nice to have at times.

I have the same problem, my one ton gets better mileage than my soccer mom Chrysler minivan. On top of that down here gasoline is $2. 99 a gal, diesel is $2. 55