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1500HD 4X4 6.0L Gas Mileage

I purchased a 2002 1500HD 4X4 in July of this year. I got 7MPG with the first two tanks of gas. I returned it to the Dealer for service. They found a calibration fault in the computer. After fixing the fault I got 10MPH (city). I took it back to the dealer and was told nothing could be done until it had about 3000 miles on it. OK. I took a 400 mile trip pulling a trailer with 2 ATV's on it and got 10MPG. I have dueled the exhaust with 2 FloMasters and 3" pipe out the back. I have installed a K&N air filter and still only get between 11 - 12MPG city. I do not have a heavy foot or make allot of quick start and stops. So I would have to say that I am very dissapointed in the gas mileage of the 6.0L engine.
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Last tank of gas i got 11.2 on my 5.3 ext cab 4wd.
I dont mean to sound like a smart @$$ but why did you buy a truck if your worried about low mpg? I do agree the 7 is low (dont get me wrong). Its a 6 liter V-8 the mpg isnt going to be that of a sedan with a 4 banger
What's your hwy milage? I'm guessing about 15?
kip
I just bought one yesterday and will see what the gas is, that is what I'm worried about.
Will the split exhaust help? How about performance chips? Tonneau cover?
I wouldn't expect much in terms of mpg increase with dual exhaust, chip, or tonneau cover even if they claim they do.
My friend Vince and I have similar 2500 4x4 Reg Cab Longbed trucks. His has an automatic, mine has a 5 speed. He gets around 11 mpg. With a slide-in camper, and weighing 7440# mine gets around 14. Both are bone stock (well, Vince has slightly oversize wheels and tires) and run well.
My worst tank has been around 10 and my best tank has been 16. Without the camper, I would expect around 17mpg. Sounds like I was lucky and go one of the trucks that returns good mileage.
Mike L
Remedy: I got a model 70 series Flowmaster on it and will see how that changes things. I want to change just one variable each time to see which has the most effect.
The muffler sounds GREAT, and I'm very impressed with the improved performance....That really blows my mind how a muffler can add that much HP.
Do any of you have better mpg the more miles you put on your engine? Am I being too anal?
I can't quantify the increase in HP, I can just tell a difference in pickup from stopped. And can really tell a difference when driving around 50-60 and increasing to 70+ while passing.
I heard after installing a catback system, the person would unhook the battery to let the computer "reset" itself to adjust to the less restrictive flow.... I wonder if that's the deal? I have'nt done it myself, just wondering if you've done it or have heard of it.
Lastly, in response to "ryanbab", just because we own trucks, doesn't mean we should not be concerned about our gas milage. I would have expected 9-10 MPG our of a Ford V-10, but certainly did not expect it from my Chevy.
To maximize performance, I recommend that all three mods you're listed be done. If I had to rate them, I'd do the following. A good catback system (not necessarily dual exhaust) as too much loss of back pressure will result in loss of power on the low end. Second a set of long tube headers. Shorty headers are only effective at high rpms. And a K&N FIPK, in that order.
One of the mods that's often overlooked since its not a bolt on is changing gears. Very cost effective from the $ per HP gain. If you have the 3.73 and want a little more zip, consider changing to 4.10 cause those 33" have probably rendered your 3.73 to a 3.42.
6.0 is?
I guess I would get better milage if I were lighter on the pedal, but thats hard to do with this truck. Aside from the ticking, knocking from the engine and loose feeling in the steering wheel,it a fun truck to drive.
When I got back home here in Utah and went back to work I still got around 14MPG...then I put on new wheels and tires (265/75/16 BFG's)and the MPG dropped down to 13MPG. I haven't reprogramed the speedo yet so who knows what I'm really getting.
I've got around 3600 miles on it so far and have been quite happy with it. No piston slap yet! New wheels and tires brought out the SHAKERADO big time but I just adjusted the tire pressure and if that don't work I'll head back for a rebalance.
It's funny, the stock tires rode very nice. I didn't notice any shaking at all. The new tires and wheels just destroyed the ride but they look cool as hell so who cares.
Sorry for the long post. It's my first, probably not my last.
fyi, I put a hard tonneau cover on and now can get 14.9 on the highway going 80mph. But Houston traffic in town lowers it b/t 12.8 and 13.5.
Don't know what to tell you on the rough ride, my mich. drive pretty smooth.
I dropped the air pressure from 50psi down to 40psi and it really made a big difference with the shakes. I'm not sure why Discount Tires had the air pressure at 50, even though I guess you could go as much as 65psi, but by dropping it the truck settled down a bunch. My gas mileage might suffer a bit now but I'll take a smoother ride any time.
Zion
Also things to ponder
Accessories like larger tires, grill guard, nerf bars, etc will add weight and also decrease your milage.
Go over to www.tirerack.com it explains it better than I can.
Went up to Wyoming for a week and got back Thursday night. Stayed in Jackson Hole and did our adventures from there.
Two trips into Yellowstone. One was a 250 mile and the other was 340 mile.
The surprise was the first trip got 19.6 mpg and the second was 19 even.
The variables were the use of 91 octane for the climbing and the 45-50mph speeds in the park.
The non-surprise was the just over 15 mpg on I-80
coming back at 80-90mph.
Truck is '98 K1500 ExtCab SB 5.7 AT 3.73 with shell and 265/75R16s.
Great trip. Not ready to be back yet.