Gas mileage help - Pirate4x4.Com : 4x4 and Off-Road Forum

RDR800 · 06-02-2005, 04:12 PM

Have a '99 3/4ton with 5.9l motor, extended cab, 4X4, auto. This truck only gets 10mpg. Synthetic motor oil and a topper are the only additions. The 10mpg is 90% freeway driving at 70mph. Are there any cheap/simple things I can do to improve the mileage? It has 80,000 miles on it. Tried a K&N filter and the mileage went down even further. Dealer has been no help, now the truck is out of warranty.

SeahawkDodge · 06-02-2005, 04:24 PM

Do you mean the 5.9? Use a scan tool and see if any codes come up. That should head you in the right direction at least.

RDR800 · 06-03-2005, 08:57 AM

Thanks for the tip SD. I will have to go find one(scan tool). The truck also seems to run quite hot. The needle sits right on the 2 of 210. I was wondering if a cooler thermostat would help?

Old Scout · 06-03-2005, 08:59 AM

Check your fuel pressure as well.

GRMhick · 06-03-2005, 10:35 AM

it could be high fuel pressure caused by a vacuum leak. Realy common on those trucks.

Also the timing could be off due to a loose timing chain.

Change out those 2 and you will have alot more power and better milage.

That said, my buddys 01 only got about 12-13 on the highway, and 10ish around town with 20k on it. By the time he sold it with around 60k, it was getting around 11 on the freeway.

My half ton gets 10-11 freeway.

It really doesnt sound THAT far off.

mopwer68 · 06-03-2005, 12:57 PM

Quote:

Originally Posted by RDR800

Thanks for the tip SD. I will have to go find one(scan tool). The truck also seems to run quite hot. The needle sits right on the 2 of 210. I was wondering if a cooler thermostat would help?

That's the milage that mine gets and the temp runs the same as yours. I thought that it was running rather cool.

Greg

sw99 · 06-05-2005, 06:10 PM

I got rid of my 5.9 because of this crap. I had the long bed w/ the 35 gal. tank and could only get 225 miles out of a tank. Granted, I had 4.56 gears and 33's but c'mon...

87 Ford · 06-11-2005, 09:41 AM

Duct tape and 6" 2x4 block............Tape block under skinney pedal! Best I can do.....Sorry!!!
10 MPG sounds good to me......Try 4-5 MPG and feel MY pain! Good luck.....

steved · 06-15-2005, 08:20 AM

Umm...what gears? If you have 4.10s, at 70mph you are sucking fuel.

My suggestion would be exhaust if you haven't done that. Try running a little better pressure in your tires. Slow down (if possible).

The 5.9s were not known for their great mileage. With a 318, 265s, 3.55s and an auto I could "squeek" 20 mpg out once in a while...I averaged 15-16mpg. The two best improvements were exhaust and ignition upgrades.

steved

79CJ7 · 06-15-2005, 11:43 AM

This is that I did to get better gas mileage. I went out and bought a 1st gen 4Runner with the 4cyl engine and use that as my daily driver. Now I get around 20 mpg every time!!

Seriously, I have a 99 Ram 1500 4x4 QuadCab with the 5.9L V8 that I nearly piss myself when it hits around 13 mpg (whether I am driving in the city or on the highway, this is what I get). And this was after I went down to 265's AT's (from 285 muds), installed a bigger throttle body, installed an aFe cold air kit, installed a 180 deg thermostat, put headers, high-flo cat, and high flow flowmasters on it, and learned to take it easy on the skinny pedal on the right.

84xtracab · 06-18-2005, 12:16 PM

My 01 Ram 2500 with a 5.9 also gets 10 mpg. I knew that before I got it though. I only put about 5k a year on it.

scout4bta · 06-20-2005, 08:50 PM

Trade it in for one with the 5.9 Litre Inline 6.

Steve

76PowerWagon · 06-20-2005, 11:54 PM

meh i get about 6-8mpg driving around town and about 9-12mpg on freeway..but 3.55's and 35" tires help the gas mileage..on the freeway anyways.

steved · 06-23-2005, 06:50 PM

I never gave it a thought...most likely it has had the "death flash" done to it...beg. borrow, or steal someones power programmer...I have heard guys having good luck with reprogramming their trucks that have been flashed.

steved

Traveller · 06-28-2005, 05:47 PM

Unfortunately power programmers are VIN locked to the vehicle they are first used on. I had the same complaint about my Vortech 7.4 K2500 Suburban, crappy mileage. I added +4 plugs, an MSD 6A ignition, dual flowmasters, a K&N intake, and a reprogramming with a power programmer.

After all the mods it had much more power, much better, firmer shifts, and I was able to squeeze 16 mpg out of it on the highway, a 2 mpg increase. With the money I'm now saving in gas I figure that I'll have paid off what I spent on those mods in 5 to 10 years.

orange318 · 06-28-2005, 10:21 PM

Well I have two ramchargers, one with a 440 that gets 7-8, one with a 318 that gets 16 all around, I only drive about 60-65 tops, and hard as it is dont beat the rigs bad. 10 seems about right, but then again look at the weight, roughly 5500 - 6000 lbs?

06-02-2005, 04:12 PM	#1 (permalink)
RDR800 Digger Join Date: May 2004 Member # 30673 Location: Helena, MT Posts: 43	Gas mileage help Have a '99 3/4ton with 5.9l motor, extended cab, 4X4, auto. This truck only gets 10mpg. Synthetic motor oil and a topper are the only additions. The 10mpg is 90% freeway driving at 70mph. Are there any cheap/simple things I can do to improve the mileage? It has 80,000 miles on it. Tried a K&N filter and the mileage went down even further. Dealer has been no help, now the truck is out of warranty. Last edited by RDR800; 06-03-2005 at 08:53 AM.

06-02-2005, 04:24 PM	#2 (permalink)
SeahawkDodge Registered User Join Date: Nov 2004 Member # 39213 Location: Virginia Beach, VA Posts: 187	Do you mean the 5.9? Use a scan tool and see if any codes come up. That should head you in the right direction at least. __________________ 98 2500 12V Cummins Quad Cab 4x4 4" Exh, Airaid int. TST #11 plate, Autometer gauges. 326hp/674ftlb 85 Dodge W150 TBI-360 Dodge, anything less is a Chevy. [URL=http://www.epinions.com/auto-review-17BE-2AED0C-3A1B8243-prod1]Dodge Dakota Lemon Law[/URL]

06-03-2005, 08:59 AM	#4 (permalink)
Old Scout IH/Rover Moderator Join Date: Feb 2000 Member # 17 Location: Aptos,Ca Posts: 13,402	Check your fuel pressure as well. __________________ I like beer. On occasion, I will even drink beer to celebrate a major event such as the fall of communism or the fact that the refrigerator is still working." BUY MY BOAT http://www.pirate4x4.com/forum/misc-...e-history.html

06-05-2005, 06:10 PM	#7 (permalink)
sw99 Registered User Join Date: Nov 2002 Member # 15049 Location: COLORADO Posts: 1,717	I got rid of my 5.9 because of this crap. I had the long bed w/ the 35 gal. tank and could only get 225 miles out of a tank. Granted, I had 4.56 gears and 33's but c'mon... __________________ 1986 K30

06-11-2005, 09:41 AM	#8 (permalink)
87 Ford Registered User Join Date: Mar 2004 Member # 28703 Location: Pair O Dice , Calif. ECV 7-11 Posts: 407	Duct tape and 6" 2x4 block............Tape block under skinney pedal! Best I can do.....Sorry!!! 10 MPG sounds good to me......Try 4-5 MPG and feel MY pain! Good luck..... __________________ 1 Ton on 3/4 Ton with lots of stuff on it..... [SIZE=3][COLOR=Red]Jackass Wheelers[/COLOR][/SIZE] Custom BodyWork By Humbug...

06-03-2005, 08:57 AM	#3 (permalink)
RDR800 Digger Join Date: May 2004 Member # 30673 Location: Helena, MT Posts: 43	Thanks for the tip SD. I will have to go find one(scan tool). The truck also seems to run quite hot. The needle sits right on the 2 of 210. I was wondering if a cooler thermostat would help?

06-03-2005, 10:35 AM	#5 (permalink)
GRMhick Pirate4x4 Addict! Join Date: Feb 2000 Member # 87 Location: I live in hotels tear out the walls I have accountants pay for it all Posts: 7,207	it could be high fuel pressure caused by a vacuum leak. Realy common on those trucks. Also the timing could be off due to a loose timing chain. Change out those 2 and you will have alot more power and better milage. That said, my buddys 01 only got about 12-13 on the highway, and 10ish around town with 20k on it. By the time he sold it with around 60k, it was getting around 11 on the freeway. My half ton gets 10-11 freeway. It really doesnt sound THAT far off.

06-15-2005, 08:20 AM	#9 (permalink)
steved Registered User Join Date: Feb 2003 Member # 17136 Location: Shoemakersville, PA Posts: 541	Umm...what gears? If you have 4.10s, at 70mph you are sucking fuel. My suggestion would be exhaust if you haven't done that. Try running a little better pressure in your tires. Slow down (if possible). The 5.9s were not known for their great mileage. With a 318, 265s, 3.55s and an auto I could "squeek" 20 mpg out once in a while...I averaged 15-16mpg. The two best improvements were exhaust and ignition upgrades. steved

06-15-2005, 11:43 AM	#10 (permalink)
79CJ7 Registered User Join Date: Jan 2005 Member # 41015 Location: somewhere in nc Posts: 68	This is that I did to get better gas mileage. I went out and bought a 1st gen 4Runner with the 4cyl engine and use that as my daily driver. Now I get around 20 mpg every time!! Seriously, I have a 99 Ram 1500 4x4 QuadCab with the 5.9L V8 that I nearly piss myself when it hits around 13 mpg (whether I am driving in the city or on the highway, this is what I get). And this was after I went down to 265's AT's (from 285 muds), installed a bigger throttle body, installed an aFe cold air kit, installed a 180 deg thermostat, put headers, high-flo cat, and high flow flowmasters on it, and learned to take it easy on the skinny pedal on the right. __________________ the invisible poster :flipoff2:

06-18-2005, 12:16 PM	#11 (permalink)
84xtracab Registered User Join Date: Jan 2001 Member # 3003 Location: North Central Mass Posts: 340	My 01 Ram 2500 with a 5.9 also gets 10 mpg. I knew that before I got it though. I only put about 5k a year on it. __________________ [color=red][b]Steve F[/b][/color]

06-20-2005, 08:50 PM	#12 (permalink)
scout4bta Registered User Join Date: Feb 2005 Member # 42545 Location: AZ Posts: 27	Trade it in for one with the 5.9 Litre Inline 6. Steve __________________ 92 W250 Flatbed 1980 ScoutII Cummins Diesel Last edited by scout4bta; 06-21-2005 at 06:46 AM.

06-20-2005, 11:54 PM	#13 (permalink)
76PowerWagon Registered User Join Date: Apr 2005 Member # 45814 Location: Reno, Nevada Posts: 47	meh i get about 6-8mpg driving around town and about 9-12mpg on freeway..but 3.55's and 35" tires help the gas mileage..on the freeway anyways. __________________ powawagon....

06-23-2005, 06:50 PM	#14 (permalink)
steved Registered User Join Date: Feb 2003 Member # 17136 Location: Shoemakersville, PA Posts: 541	I never gave it a thought...most likely it has had the "death flash" done to it...beg. borrow, or steal someones power programmer...I have heard guys having good luck with reprogramming their trucks that have been flashed. steved

06-28-2005, 05:47 PM	#15 (permalink)
Traveller Registered User Join Date: Jun 2005 Member # 49519 Posts: 77	Unfortunately power programmers are VIN locked to the vehicle they are first used on. I had the same complaint about my Vortech 7.4 K2500 Suburban, crappy mileage. I added +4 plugs, an MSD 6A ignition, dual flowmasters, a K&N intake, and a reprogramming with a power programmer. After all the mods it had much more power, much better, firmer shifts, and I was able to squeeze 16 mpg out of it on the highway, a 2 mpg increase. With the money I'm now saving in gas I figure that I'll have paid off what I spent on those mods in 5 to 10 years.

06-28-2005, 10:21 PM	#16 (permalink)
orange318 Registered User Join Date: Jul 2004 Member # 33428 Posts: 91	Well I have two ramchargers, one with a 440 that gets 7-8, one with a 318 that gets 16 all around, I only drive about 60-65 tops, and hard as it is dont beat the rigs bad. 10 seems about right, but then again look at the weight, roughly 5500 - 6000 lbs?

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