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How to get better MPG, it sucks!

turbovanman

I has boost, :O)
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My brother just bought a 09 3500 PU, 4x4, 4 door, full load and its getting around 12 mpg combined. I saw the other thread so some are around this, some are higher. What can we do to it without voiding the warranty, IE air filter housing, cat back, or an inline programmer as we can't tamper with the stock computer, etc. :(
 
You have to wait until the motor gets broken in and loosens up a little. Try a little fuel supplement also (Stanadyne or Power Service). Be sure to keep the tires pumped up, and drive the truck the same way to get an accurate result of the tests changes you do.
 
Thats good advice. When I traded in my 04, I left 18 and some change to 11mpg. I didnt understand why it was so low and it made me sick. Once I hit 6000 miles, it continued to rise and leveled off at 22mpg at 70 mph. Basically, my mileage doubled in time.
 
Mine started at 10 to 13 from new until about 26K when I decided to get the programer and exhaust. Now I get from 13 to 15. Mostly road and some highway mix. I think on a good highway trip I may see 16 to 18. At least I hope to.

I didn't buy it for the milage.
 
09 CC 2500HD 4x4, I bought a new vin matched ecm $184, already have efi live $99 new vin license with about a 430rwhp tune, put a 4inch turbo back exhaust pulled off my 02 I traded in. Went from a pretty consistant 12.5-13mpg to 16.5-17mpg with only 3500miles on the truck. 315/75/16s I know there may be issues with the regeneration numbers and what not but I can put the stock ecm and exhaust back on if I have problems and need to take it to the dealer. I plan on owning the truck for a long time, beyond being payed off so I will see my money back in the mileage. It is my understanding that the inline programmer does not download a tune but modifys the stock signals and the modifyed limits rpm limit, max torque limits if exceeded may possibly be recorded in the ecm and tcm? I don't know that for a fact but that is my understanding for an LMM.
A hard compound close tread pattern tire filled to max psi and a light foot is the only/best option for best mpg, and a broken in motor that will keep a warranty without issue that I see.
 
i guess im one of the lucky ones on the new lmm motors with about 15 around town and any where from 20 to 24 on the highway(65-70mph) but just dont drive heavy on the throttle and as it gets more miles it will get better. my buddy wasnt doin to good on mpg's and at about 30,000 it went up pritty good. these motors take some time to "break" in. but power adders have helped me if you can stay off the throttle around town and not break the 2,000rom range. i have had many say BS to my mpg's until we do a road trip and then they are surprised. i didnt think when i bought the truck i would get that good of mileage but hey ill take it if i can. my dads buddy had and 05 tacoma that didnt get the mpg's that i was getting loaded with a quad and 20' trailer and he was shocked cus he had an empty truck. so i lucked out with what i got. but if you can keep a light foot till she breaks in youll see a good jump in mpg's
 
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