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Reprogramming 09 Chevy Truck

KCA

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KCA Enthusiast

KCA

Posted
Posted

Hi everyone, New guy here. I know this has been brought up before but wanted to check with you all before I do this. I've got a stock 2009 ext. cab 5.3 3.42 rear with 24,000 miles. By what the dash tells me the best I can get out of the truck is 14mpg. More than once on the hwy. I've got 13.8. I've watched it switch from v8 to v4 and back to v8 just by taking a breath. I know you all talk about using a programer by BB but nothing about the Chevy dealership. I talked to them the other day and they recommended turning the afm off and run it on all 8. They said it would not void the warranty. They said it should get me another 2mpg. Does all this sound right? Or is there something else I can do to improve the mileage? The dealership checked the truck out and said everything checked out ok. Thanks for any help.

Stevens03 Senior Enthusiast

Stevens03

Posted
Posted

Thats a first coming from the dealership. Most are against it. I'd be surprised if you got 2mpg more by turning it off. I turned mine off, and saw no difference.

nickvrebel Senior Enthusiast

nickvrebel

Posted
Posted

how fast are you driving on the highway? are you in hills and are you maintaining a constant speed?

KCA Enthusiast

KCA

Posted
  • Author
Posted
how fast are you driving on the highway? are you in hills and are you maintaining a constant speed?

 

Thanks all for the response. Hwy miles were fairly flat. Speed was right at 70. Even with the cruise control on it still goes in and out of afm. I had a 1992 truck that still got 18 in town with 200,000 miles on it. Wished I never sold it. Been thinking about buying an older model and redoing it and sell this one. Thanks again.

Snow White Enthusiast

Snow White

Posted
Posted

if you are getting 14 and that checks out with the old school hand calculation, I'd say there is a problem for sure. You should be getting at least 16. Are your tire pressures up, how much ethanol is in your fuel? A lot of things can contribute, but that doesn't sound right.

KCA Enthusiast

KCA

Posted
  • Author
Posted
if you are getting 14 and that checks out with the old school hand calculation, I'd say there is a problem for sure. You should be getting at least 16. Are your tire pressures up, how much ethanol is in your fuel? A lot of things can contribute, but that doesn't sound right.

I'm running 40psi in the tires. 87 oct. don't remember the ethanol amount. Shell gas. Calculator said 14.189 mpg. This is something else I was wondering about. I was reading on another sight about people having to have their lifters replaced because they went bad under 50,000 miles. Know anything about that? Thanks.

nick3941sd Enthusiast

nick3941sd

Posted
Posted

I got my truck BB tuned and turned off the AFM and saw a little bump in my MPG. The performance gain is a nice plus also. If your on the fence about a BB tune I'd say go with it. BTW im running the 93 octane tune.

KCA Enthusiast

KCA

Posted
  • Author
Posted
I got my truck BB tuned and turned off the AFM and saw a little bump in my MPG. The performance gain is a nice plus also. If your on the fence about a BB tune I'd say go with it. BTW im running the 93 octane tune.

Thanks everyone. I'm happy with the power the truck has. Just wished it would get 2-3 more mpg.

z71duke Enthusiast

z71duke

Posted
Posted

"I've got 13.8. I've watched it switch from v8 to v4 and back to v8 just by taking a breath. "

 

I have had the same experience... Mine is a Crew Cab and I have never seen an average of over 16, even with

stock 245's. I expected a drop with my new Toyo MT's, but was hoping for better mileage than my current avg of 12.9 calculated at 75mph, flat hwy, cruise, mild acceleration, etc. It very rarely stays in V4.

 

I dont believe anything is "wrong" with the truck, it has never thrown a code and has been flawless over the year I've had it. I just have not seen anyhting near some of the mileage returns posted here.

nickvrebel Senior Enthusiast

nickvrebel

Posted
Posted

on flat land at about 70 mph you should be getting around 16-16.5, maybe even 17 mpg.

 

your truck won't stay in 4 cyl mode at that speed, it's just too much power required and wind resistance to maintain that speed. I have adjusted my tune myself a little (look for my thread in this section) and achieved much better economy at around 55-60 mph

Snow White Enthusiast

Snow White

Posted
Posted

maybe your brakes are dragging or something? I vary rarely get below 16, I live in hilly CT and drive 30/70 city/highway and that mileage is in the winter, it mostly depends on how much i use remote start and how long i let it sit to warm up.

z71duke Enthusiast

z71duke

Posted
Posted

How would one go about asking the dealer about poor mileage? As I mentioned, there is no obvious sign of problems... The truck runs perfect, I dont think anything like stuck brakes is going on, it is much quicker than my old Silverado (with the 4-speed) and far ahead of my 05 F150 with the 5.4.

KCA Enthusiast

KCA

Posted
  • Author
Posted
How would one go about asking the dealer about poor mileage? As I mentioned, there is no obvious sign of problems... The truck runs perfect, I dont think anything like stuck brakes is going on, it is much quicker than my old Silverado (with the 4-speed) and far ahead of my 05 F150 with the 5.4.

 

 

When I took mine in, I told them about the mileage. They said they would check the settings on it. But they didn't find anything. One other thing some of you might not know. I didn't till I checked it out. Just for the heck of it I checked my truck out on carfax before I took it in. Found out it showed the times I had the oil changed. When I took it in for the mileage thing I asked the guy there if checking the truck out will show up on carfax. He told me " What was I talking about. Nothing shows up on carfax. He acted like a jerk. I told him I already check it. Showed the day they received the truck when I bought it. When I picked it up. Etc. He just walked off and acted like I did'nt know what I was talking about. Just a heads up.

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