# 6.7 MPG GMC 14' Box Truck



## plumberkc

I just bought a 1995 GMC w4 with only 65,000 miles on it. I really like all the space and love not having to pull a trailer anymore. I was expecting to get around 9-11 mpg but under 7 mpg is pretty bad. 

Is there anybody else that has a similar truck that is getting better gas mileage. I checked the tire pressure and it is good. It has a lift gate that weighs close to a thousand pounds and I have it semi loaded with stuff. Other than that I was thinking about a cold air intake or maybe a chip.


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## DesertOkie

Post a pic, the box truck I ran in got 10-12 but it was a SRW and a ford.
Like this but a ford. The dually version(a little bit wider and longer) only got 9-10


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## Titan Plumbing

A chip will give you a MPG or 2, don't waste the money on a CAI, just get a K&N drop in.


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## ditchdigger

I had 07 2500 got about the same had to sell that biotch


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## plumberkc

Titan Plumbing said:


> A chip will give you a MPG or 2, don't waste the money on a CAI, just get a K&N drop in.


One or two MPG would mean an extra 60 miles per tank. :thumbup: What is a CAI?

This is pretty much my truck, except mine is a GMC. I'll take some pictures after I clean up the wheels some.


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## DesertOkie

That seems low to me.


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## plumberkc

Nevermind the COI question...Cold Air Intake :whistling2:


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## plumberkc

DesertOkie said:


> That seems low to me.


 Mine might actually be 1' taller than the one in the pic.


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## Titan Plumbing

CAI=Cold Air Intake.

You might get more of an increase, the whole idea behind the tuner on a gasser is to get the big load moving quicker.

ETA: Get a tuner that is programmable...Superchips is not your friend, think SCT.


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## deerslayer

What motor is in it?


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## DesertOkie

plumberkc said:


> Mine might actually be 1' taller than the one in the pic.


Six speed or auto? I ran ice in a 92 and it was pretty good on fuel, and it was loaded down.


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## plumberkc

deerslayer said:


> What motor is in it?


5.7 Gas


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## plumberkc

DesertOkie said:


> Six speed or auto? I ran ice in a 92 and it was pretty good on fuel, and it was loaded down.


It's an automatic. Thing is I really don't have all that much in it right now. I wonder how much that lift hurts gas mileage. I would be okay with a ramp if it helped me on fuel.


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## deerslayer

Have you started with the basics?
Proper oil and filter, air filter, plugs wires cap and rotor.
I would thenjack it up and check all the wheel bearings and make sure the brakes have a good clean release.
I have had alot of 350 chevrolet's around that year and never seen any difference in mileage from a chip. YMMV


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## deerslayer

I forgot to mention fuel filter!
I would also try some lighter weight synthetic oil in maybe a 5w30 if it's rated for it! That can increase mileage slightly as the crank will have slightly less resistance!


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## AlbacoreShuffle

plumberkc said:


> It's an automatic. Thing is I really don't have all that much in it right now. *I wonder how much that lift hurts gas mileage. I would be okay with a ramp if it helped me on fuel*.


I have the opposite view.
That lift will extend your working life by years, at least it would for me.


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## Titan Plumbing

deerslayer said:


> Have you started with the basics?
> Proper oil and filter, air filter, plugs wires cap and rotor.
> I would thenjack it up and check all the wheel bearings and make sure the brakes have a good clean release.
> *I have had alot of 350 chevrolet's around that year and never seen any difference in mileage from a chip.* YMMV


That is why I suggest an SCT tuner...it is programmable, an experienced tuner can do some pretty cool things even tune the tranny. I ran the Superchips tuners for a number of years with the 3 basic tunes, then I went to SCT and had a whole nuther experience.


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## plumberkc

Problem is, I'm not an experienced tuner. :laughing:


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## SlickRick

plumberkc said:


> 5.7 Gas


My 6.0 does much better than that.


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## Mississippiplum

Id say you need a diesel

sent from the jobsite porta-potty


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## Titan Plumbing

plumberkc said:


> Problem is, I'm not an experienced tuner. :laughing:


Easy enough, just go to a Chebby truck site and find you an experienced tuner...Prolly for 50 bucks or less you can have a great tune. I may even know someone, I do know they can tune the shiot outta a diesel.


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## deerslayer

Titan Plumbing said:


> That is why I suggest an SCT tuner...it is programmable, an experienced tuner can do some pretty cool things even tune the tranny. I ran the Superchips tuners for a number of years with the 3 basic tunes, then I went to SCT and had a whole nuther experience.


Thanks for the clarification Titan, I am not experienced with those.


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## deerslayer

Titan Plumbing said:


> Easy enough, just go to a Chebby truck site and find you an experienced tuner...Prolly for 50 bucks or less you can have a great tune. I may even know someone, I do know they can tune the shiot outta a diesel.


My diesel on the other hand is bad to the bone running a banks tuner!


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## SlickRick

I have programmer on my Z71. I can tune it for economy, shifting, or make it white smoke the tires.


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## plumberkc

Mississippiplum said:


> Id say you need a diesel
> 
> sent from the jobsite porta-potty


I wanted a diesel but I have heard bad things about diesels that do a lot of stop and go driving. Seems like they start having issues at around 100,000 miles. Plus they cost a little more, I picked this truck up for $4600 plus it was already stocked with shelves from a previous plumber.


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## rjbphd

Would Amsoil works.. from I read all the fluids in the vehicle must be replaced with Amsoil oils to get the mileages improvement. $$$$$$$$$


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## SlickRick

That 5.7 is what I have in my 1/2 ton. I get close to 20 mpg.


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## rjbphd

SlickRick said:


> That 5.7 is what I have in my 1/2 ton. I get close to 20 mpg.


 Damn, I'm lucky to get 12 on my 1 ton srw gmc with reading untily box..with 6.0 engine


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## SlickRick

rjbphd said:


> Damn, I'm lucky to get 12 on my 1 ton srw gmc with reading untily box..with 6.0 engine


I have the 6.0 in my 1 ton KUV and I prolly get around 14 without a programmer, most of mine is highway.


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## plumberkc

Is it possible to get a new box for my existing truck? I can't even find a website or company that sells just the box. It's gotta be a lot less than buying a whole new truck. 

My current setup has a ceiling height of 88", I could lose around 12" and not miss it. The box that's on there isn't in great shape either, especially the back door. 

One other thing that I noticed is that the box is sitting on top of 2 treated 2x4's that sit in between the truck and the box. I think this is necessary to avoid hitting the tires. I am wondering if these could be removed and the new box would have cut outs inside the box for the wheel. This would also make the truck box sit lower for easier access and might be able to replace the lift with a winch system. 

Lower Truck = Better Gas Mileage :clap: A wind deflector might help as well.


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## rjbphd

plumberkc said:


> Is it possible to get a new box for my existing truck? I can't even find a website or company that sells just the box. It's gotta be a lot less than buying a whole new truck.
> 
> My current setup has a ceiling height of 88", I could lose around 12" and not miss it. The box that's on there isn't in great shape either, especially the back door.
> 
> One other thing that I noticed is that the box is sitting on top of 2 treated 2x4's that sit in between the truck and the box. I think this is necessary to avoid hitting the tires. I am wondering if these could be removed and the new box would have cut outs inside the box for the wheel. This would also make the truck box sit lower for easier access and might be able to replace the lift with a winch system.
> 
> Lower Truck = Better Gas Mileage :clap: A wind deflector might help as well.


 Have you check Reading truck boxes??


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## rocksteady

I was looking at cab-over trucks similar to yours and the Isuzu NPR and I heard terrible stories about gas mileage. Diesels getting 10 mpg and gas below 8. I think it had a lot to do with a combination of aerodynamics and gearing. For some reason, the cab-over trucks are geared like rock crawlers. I decided to go with a more standard E350 diesel due in large part to the mpg figures I was hearing online.









Paul


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## plumberkc

So you purchased an E350 box truck... What kind of gas mileage are you getting?


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## rocksteady

I have a 2003 7.3l Powerstroke, DRW E350 running right at the gvw of 11,400 lbs and I get about 11.5 mpg. This with about 280k on the clock. 









Paul


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## plbgbiz

plumberkc said:


> I just bought a 1995 GMC w4 with only 65,000 miles on it. I really like all the space and love not having to pull a trailer anymore. I was expecting to get around 9-11 mpg but under 7 mpg is pretty bad.
> 
> Is there anybody else that has a similar truck that is getting better gas mileage. I checked the tire pressure and it is good. It has a lift gate that weighs close to a thousand pounds and I have it semi loaded with stuff. Other than that I was thinking about a cold air intake or maybe a chip.


That's why I sold our KUV to a competitor. 6mpg was just too low.


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## plumberkc

plbgbiz said:


> That's why I sold our KUV to a competitor. 6mpg was just too low.


6 mpg for the KUV too? 

http://hvac-talk.com/vbb/archive/index.php/t-99169.html

This guy was claiming about 11 MPG with a KUV. Those things sit so much lower to the ground you would think the mileage would have to be a little better.


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## plbgbiz

Yeah, very disappointing. 

One reason I think was the ridiculously low gear ratio. We had a one ton dually. On the scales empty it was within 500 pounds of its GVW max. Too much box not enough truck. I think the weight issue was also why we couldn't keep the front end lined up and kept chewing up the front tires. I got rid of it before its first anniversary.


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## SlickRick

My KUV is not a dually, and I promise my mileage is decent.


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## plbgbiz

SlickRick said:


> My KUV is not a dually, and I promise my mileage is decent.


I don't doubt it. I think one factor is the guy driving mine was not the same guy paying for the gas.


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## plumberkc

So Biz, what did you replace the KUV with?


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## SlickRick

plbgbiz said:


> I don't doubt it. I think one factor is the guy driving mine was not the same guy paying for the gas.


I KNOW that could be right!


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## deerslayer

SlickRick said:


> I have the 6.0 in my 1 ton KUV and I prolly get around 14 without a programmer, most of mine is highway.


I have the same setup as you and I average 12-13 but I do drive it pretty hard and it's not flatground or all highway driving for me after all I am in the city of seven hills, it's also loaded at about 9,500 lbs give or take


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## plbgbiz

plumberkc said:


> So Biz, what did you replace the KUV with?


We have six Chevy Express 2500's on the road. Average 13 to 18 mpg depending on the driver and the rigging. I could have never survived in a cargo van on my own but with a few trucks it is better for us.


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## Don The Plumber

plumberkc said:


> I wanted a diesel but I have heard bad things about diesels that do a lot of stop and go driving. Seems like they start having issues at around 100,000 miles. Plus they cost a little more, I picked this truck up for $4600 plus it was already stocked with shelves from a previous plumber.


Just curious as to why the other plumber sold the truck? Man.... 17yrs old is just frightening to me, but if you can, or like to fix em, I guess its ok.

I am buying a new Ford 4500, & picking it up this week. I special ordered it, & getting suspension beefed up, before I change over. This truck has a 55 gal gas tank. 

My current truck is a 2001, 3500 GMC that I bought new in 2003. I only got 90K in miles, & have had too many breakdowns, & costly repairs. Also the box is corroding. Thats why I couldn't fathom, dealing with a 17yr old truck, no matter how many miles are on it. I take good care of my truck, & always get oil & trans fluids changed at recommended times, & what ever the truck needs, I get it done, cuz I can't afford to be down, cuz if the truck is out of commision, I'm out of business.

I know I don't drive as far a most, I stay within a 20 to 30 mile radius, but some of you that get 200k or more miles out of these vehicles, without having major problems, is beyond me. It gets to a point, where its not economical for me, to keep fixing the old, & wondering, what's next.


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## plumberkc

Not sure why the old plumber sold the truck, it was probably due to the poor gas mileage. I know what you mean about needing a reliable vehicle. If something does break, I still have my pickup and a 12' enclosed trailer that I can work out of. I figure if I get two years out of it without any major repairs, I'll be doing pretty good.


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## Master Mark

4500 is not too bad on the price with a lift gate....
the lift gate alone is worth aboout 2500 new...65,000 miles says that this was never used probably due to the crappy mileage

I am getting about 10mpg with a 6.0 gas motor in a 
2006 chevy box van... 12 foot box with an alluminum tommy gate.... 

 The tommy gate is my left nuts best freind
my right nut is pretty fond of that gate too ......:laughing::laughing::yes:


sell the truck but keep the tommy gate for the next one


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## plumberkc

I finally have slowed down enough to pay some attention to servicing this truck. 

In order to check the tire pressure in this truck you need a semi truck tire gauge. The back tires were set at 50psi instead of 80psi, so that should help.

I also changed the fuel filter, spark plugs, plug wires, oil, and added a K&N. 

This truck is pretty easy to work on. Changed the plugs in less than 30 minutes, took over 6 hours on my 2005 ford. I'll give an update as soon as I can check the mpg.


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## Master Mark

plumberkc said:


> I finally have slowed down enough to pay some attention to servicing this truck.
> 
> In order to check the tire pressure in this truck you need a semi truck tire gauge. The back tires were set at 50psi instead of 80psi, so that should help.
> 
> with only 50psi in the rear tires
> you had to be fish-tailing down the road...
> 
> I can tell when I have got a low tire for that very
> reason.


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## gear junkie

Look into getting he service manual...best tool you can by for auto repair. Not talking about a haynes or chiltons but the real manual that is about 6" thick.


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## plumberkc

Finally seeing some improvement in gas mileage. I replaced the vent for my fuel tank and saw a steady 1 MPG increase, then I replaced my O2 sensor. I'm getting an extra 50-60 miles per tank and averaging over 8MPG.


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## BOBBYTUCSON

Isuzu national public radio is an amazing setup


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