cabe227

What really grinds my gears is that i have taken it back to different dealers 4 times and they have the same answer-- it needs to break in--- The truck has 8,000 miles on it. the thing is broken in. In the last 800 miles or so I added an Airade CAI intake and a catback flowmaster. Mileage has increased by 0.0 MPG... adding a tonnau cover and a superchips cortex computer this week.... IF MPGs DONT INCREASE THEN I AM TRADING MY TRUCK!!!!!!!!!!!!!
GM has been my childhood brand, but if they keep putting out this CRAP then I may have to look somewhere else......
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ANYONE HAVING THE SAME ISSUE WITH THE 2011 5.3 FLEX FUEL W/ 3.42 GEARS./... CONTACT ME AT CABE227@YAHOO.COM.. I HAVE 34 PEOPLE ON PETITION ALREADY FOR POOR mpg/false advertisement for the GM LC-9 engine

Wade Quick

Could miles per gallon be related to the revolutions per minute (RPM) that the engine turns? It relates to the cubic feet per minute (CFM) of the air/fuel mix passing through the heads and cylinders and that is the cause of the fuel consumption. Keeping the rpm down below 2000 and in most cases closer to 1500 rpm has been a boost to my mpg over the years, whatever vehicle I drive. Nixon mandated the 55 mph law for this reason as a way to reduce national fuel consumption in the 1970's. Remember the oil embargo?

nkh34

on the octane issue i agree with it being a waste of money if you ride snowmobiles then you should know this. If you are racing and running 110 octane then you have to redo computers and a bunch of other stuff. most sleds are supposed to run 91 if you run 83 you can easily tell that your sled is running like junk. for this reason i have a friend that set up another computer on his sled that allows him to pick between 87 and 91 and it works well. And as stated earlier a brand new motor wont be fully broken till around 15,000 miles. and the tonnau cover i have been told will help alot. and we also all know that auto dealers arent the most honest people my dad always says subtract 5 mpg from what the sticker says also said was when they get those ratings it is in ideal terrain and weather so unless your driving through kansas on a great day you probably wont get that. give your trucks some time they are like dogs its a puppy now and until it is adjusted to you its gonna do some stuff you dont like just feel it out before you jump the gun and trade a good truck and end up losing money on it. and if your 2011 is riding smooth but not getting great mileage then your still doing better then that group that their trucks shake and quake anywhere past 45 MPH

cabe227

Well I have installed a airade intake and a superchips computer on the truck along with a tonnau cover. The cover didnt make any difference, the intake didnt make a difference until i tuned the computer. i was getting between 10.5-10.8 on E85. Now that i have run 2 tanks through of 87-91 here are my results. ACM or DOD still doesn't work. i never see 4 cyl. mode. But now im getting about 18.2-19.5 mpg hyw. @ ~60-65mph... any faster and it starts to drop to about 14.5-15. The truck seems to run smoother and doesn't downshift so hard with the extra power on hand. Point is I shouldnt have to do all that to get honest fuel economy results. Its not my daily driver but come on.

grandpa3437

I have a 2010 and the gas mileage isnt any better. Uses oil too. WATCH OUT !!!

WOOD828

@Delbert51I just found your post concerning the gas mileage on your 2011 Silverado. I purchased the same vehicle in December, 2011. I am experiencing the same poor gas mileage...max 15 mpg highway. Also took my truck back to the dealer and they said a lot of people are complaining. Said the Active Fuel Management System only kicks in when the truck is coasting down a hill. It appears that the Active Fuel Management System is non-existant on this truck although it is stated clearly on the "sticker." Also, page 9-40 in the manual states "when less power is required, such as cruising at a constant vehicle speed, the system will operate in the half cylinder mode, allowing the vehicle to achieve better fuel economy." This is totally false information. I have called General Motors with no help. I have contacted an attorney to see what can be done. Was wondering if you were able to get any kind of resolution to the problem. Please e-mail me. Thanks!

midshark

wood828, I don't know if Delbert51 will respond, he only posted twice and it was over a year ago.
I just bought a 2012 4x4 extd. cab with the 5.3 last month, and it sounds like some of us should start a club. I ran 2 tankfulls on the highway only, and both times I got 14.6 mpg. Around town/combination is 13.5. That's not at all what I thought I was signing up for. My AFM only shows V4 mode when I am decelerating or going downhill. My 2002 needed to be replaced, and a high mpg of 16 highway for that truck was one of the reasons I decided to take the plunge and buy new and see how close I'd get to the advertised 21 mpg. What a crock! I paid $35,000 for a 10 year newer truck that gets 1.5 mpg less than my old one. I wish now that I had kept my 2002.

rutbuster1

I've got a Silverado Z71, 4x4 , 5.3L, extended cab and 3.42 gears. Presently, it has over 8000 miles on it. I purchased the truck in December 2011. I am VERY DISAPPOINTED with the fuel mileage thus far. I do not put my foot in it. The best mileage it has gotten thus far is 15.4 mpg. I love the truck but the "claimed" mpg is absolutely FALSE! There has to be something that can be done on such FALSE representation. The sticker rating is what lead me in to trade my Tacoma. BIG MISTAKE!! I am pleased with the truck other than the mpg. If I would have known that 15.4 mpg is the most I would get, I would never have got it. Absolutely RIDICULOUS!

rutbuster1

Join the club of disappointed owners. Other than the mpg, I love it though. If fuel prices keep going up, I may trade it in another year. Just sayin. Very disappointing.

sheadmo

gm will not do anything but tell you every thing is in gm specs nothing else they can do.i took mine to 2 different dealers got 2 different stories finally the service manager told me its all about sales gimmick mpg ,sure ive been told its not broke in,after mkt tires which are exactly the same size as gm 20,s aggressive driver,what kind of fuel i burn which is top tier regular the best mileage i get on hiway running the speed limit not in perfect track condition like the gm does is 13.2 on hwy,false advertising i believe