Stand back! I think she's going to blow...

[rsgs]

I am almost in disbelief of my fuel economy lately. This past weekend, I got an actual 25.1 mpg! This all started happening several months ago when I did my usual swap the big BFG's and wheels for the summer wimpy 245 towing tires and wheels. I had been pushing the 20 mark, but over the last several weeks, the mileage has gotten better and better! The only thing I can think of is that the whole motor is getting ready to explode. This mileage couldn't happen at a better time. I just wonder why now after 55k?

[Jim Brzozowski]

Man you must drive slow. I recorded 21.2 mpg last week and thats the slowest I've ever driven and the most mileage I've recorded in this truck. I don't know how you do it, maybe one of your sneeky neighbors is adding fuel to your truck at night while your sleeping, I actually know a group of guys that did that to a guy at work for a week or so. He couldn't figure it out until someone fesed up.

[rob@rone.ca]

To get that kind of mileage, what is the weight of your truck? 2500 or 3500, single or extended cab, standard shift or allison? speed of tailwind? was the weekend trip all downhill?

If that keeps up, you could probly sell that one for more'n you paid for it!!!

Maybe it's only running on 4 cylinders (limp mode) - 4's are supposed to get better mileage!!!

[rsgs]

I have a 2500 Duramax with Allison trans and a Crew Cab. I have done nothing other than the tire change. When I first started noticing the improvement in mileage, I was running 3 hours north and 3 hours south here in Michigan. I had the tailgate down (which I firmly believe works!). I actually run at 70mph on cruise without the a/c. Now when I do put the air on, it does drop 1-2 mpg. About a month ago, I did put my cab back on the box but noticed no difference. I like the trick of adding fuel. hehehehe. Sounds like something I would do. And the really weird thing is, the performance/response of the engine has never been better. I am convinced she's going to blow!

[Kennedy]

How many miles on the fuel filter? I have heard second hand from a relieable source that when the fuel filter is on it's last legs the mpg comes up.

I would NOT recommend running long change intervals, but interesting observation/claim nonetheless...

[rsgs]

I change oil, fuel, and trans filters every 5k.

[BIGJEFFSCV]

The most that I can get is 16.
I read claims on this forum about higher, but I don't know how it is happening!
Frustrating. 02 CCLB 4x4 D/A
Freeway average 70-75 mph. This is all around average.

[rsgs]

I have no idea either. The best I could get was about 17-17.5 for two years now. For no reason, no explaination -bang- I'm getting great mileage. It's making me REAL nervous...

[bd1028]

I was getting 21 to 22 mpg since i bought the truck .the truck is all stock 184000 miles.they just replaced all the injectors now i am down to 16.5 to 17 mpg that sucks but the smoking problems are gone they also put the new gm filter
on it.


02 Duramax ext cab
2500 185740 miles

[mdadgar]

Originally posted by BIGJEFFSCV:
The most that I can get is 16.
I read claims on this forum about higher, but I don't know how it is happening!
Frustrating. 02 CCLB 4x4 D/A
Freeway average 70-75 mph. This is all around average. That's exactly my experience, too. I got one tank at 20.02mpg but I had the cruise locked at 55.

My towing mileage is in line with everyone else's, but my empty mileage is way lower (exactly like yours).

- Mark

[markrinker]

Yesterday was first haul with a 'new' 2001 K2500HD reg cab long box with 75K miles. (Injectors, fuel rail and fuel pressure sensor all have been replaced under warranty.)

Averaged 16mpg over 390 mile day pulling 4K flatbed trailer, half of those miles with 8500# of steel. Thats 2-3 mpg better than the '05 LLY would do, under the same circumstances.

I'm thinking unloaded mileage should be 20-22mpg.

[chrisinkanata]

I posted this on the fuel mileage survey a while ago. My experience seems to be excellent based on other posts, but I can't touch this 25.1 US mpg. The tires definitley make a difference.

'With very conservative driving i.e. 100-105km/h (62-65mph) unloaded over long distance consistently 26.5-26.9 Imperial mpg (22.4 US mpg). I have repeated this many times in the warm summer months with the stock 245's. BTW...speedo out by 2-3 mph according to my GPS. Understandable though since the tires are almost done and will be replaced over the winter while the snows are on the truck.

Towing - 7000lbs travel trailer (truck has a cap tapered up towards the rear and acts as a very good windbreak) ---- again very conservative driving and 18.3 to 19 Imperial mpg depending on terrain. (15.2 US mpg).

City summer driving same as towing.

I do notice that when I put the snows on (265's) the milaege takes a substantial hit. Empty hwy falls to 21-22 Cdn (17.5 US mpg). Two parts to that I think....larger tires (I use the GPS to record distance, not the odometer) and far colder temps. I wanted to replace the 245 summer tires with 265's but don't think I will based on that difference. I should put the snows on now while it's still fairly warm and see what the mileage is like.'

Chris

--------------------
2002 2500HD Crew Cab 4X2 D/A

[motovet]

Originally posted by SoTxPollock:
Man you must drive slow. I recorded 21.2 mpg last week and thats the slowest I've ever driven and the most mileage I've recorded in this truck. I don't know how you do it, maybe one of your sneeky neighbors is adding fuel to your truck at night while your sleeping, I actually know a group of guys that did that to a guy at work for a week or so. He couldn't figure it out until someone fesed up. That would be an expensive joke now days. :eek:

[Turbo Al]

Well I would hesitate to post if someone else hadn't of made the claim first. On my way back from Hunting last year my truck took an unexpected improvement of about 60 miles per tank for no reason at all -- this was at about the 40,000 mile mark -- so I guess it just plain decided to break in.
Relax it's been a year for me and it hasn't blow up yet. tongue.gif
I just got back (with a Nice Elk) but can't really get a mpg on this trip since so much of it was sloggin through mud in 4x4.
Al

[markrinker]

The best mileages I've seen happen during my hunting trips in the fall. My only explanation is the moderate temps - not too cold, not too hot, the length of the trip, and generally not in a hurry to get there.

BTW: My buddies at hunting camp are too cheap to put fuel in my tank.

[Rhoward225]

When mine was new, averaged 17 to 18 mpg., Then I added the exhaust and intake at about 30,000. MPG did nothing but go up to averages between 22 to 24 mpg. Then at about 135,000 miles, and after adding the Edge, went to 16 to 18 mpg, and smoking allot under a load. Loaded mpg stays around 12. Really worried about what's going on!

[Mark Heiken]

[QUOTE] quote:
--------------------------------------------------------------------------------
Originally posted by SoTxPollock:
Man you must drive slow. I recorded 21.2 mpg last week and thats the slowest I've ever driven and the most mileage I've recorded in this truck. I don't know how you do it, maybe one of your sneeky neighbors is adding fuel to your truck at night while your sleeping, I actually know a group of guys that did that to a guy at work for a week or so. He couldn't figure it out until someone fesed up.
--------------------------------------------------------------------------------

That would be an expensive joke now days.


The proper way to do this is to pull fuel out of the targets tank for a few weeks. Then start adding it back a little at a time. That way his milage goes down and then up. Really freaks them out and at no cost except time and effort.

[Powerstroke73_2_Duramax66]

No one has mentioned this yet but