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2007/2008 Silverado and Sierra Active Fuel Management Problems

106 messages,  Last post on Sep 01, 2009 at 9:04 PM

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What is this discussion about? GMC Sierra 1500, Chevrolet Silverado 1500, Fuel System, Truck


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#6 of 106
AFM by teamimpact
Nov 11, 2007 (12:23 pm)
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My 2007 Vortec Max has only one problem It Runs Great and my wife thinks I love my truck more than her
#7 of 106
6.0 MPG by asylum575
Nov 19, 2007 (3:07 pm)
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What kind of fuel economy do you get with a 6.0 with active fuel management
#8 of 106
Re: 6.0 MPG [asylum575] by 12ozcurls
Nov 19, 2007 (8:29 pm)
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Replying to: asylum575 (Nov 19, 2007 3:07 pm)

yeah i second that..whats everyone gettin in terms of milage..
#9 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [cadillac5] by santaman58
Nov 26, 2007 (12:45 pm)
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Replying to: cadillac5 (Oct 17, 2007 4:08 pm)

Hey I'll stand right there with you and agree with there being a problem. My 2007 New Body Silverado 6.0 liter with max trailering has been running like crap since day one. Thought it would break in and the issues would go away...not! Its been to dealer and they told me it needs more time to have the fuel cells trimmed because it is a "smart" truck...I HAVE 3000 MILES NOW and it still runs like crap. It stutters and tugs going up hills and doesnt know when to shift. Plus it has a distinctive rough idle. It has a subtle noticeable pop when AFM kicks in and it sucks to drive it. It is going back to dealer again soon but they are saying that it might take 5000-7000 miles before the brain learns my driving habits. HEY!!!!!!!!!!!!!!! I shoudlnt have to wait for that long to have a truck run correctly! THERE ARE PROBLEMS OUT THERE WITH THESE TRUCKS CAUSE I HAVE ONE ONE OF THEM! If I drive in third gear and AFM doesnt kick in then the problem is gone...rough idle still exist though....so I say that the AFM is the culprit. GM needs to address this issue and notify dealers how to correct it. I will continue to take mine back til its fixed or lemon lawed! When you spend this kind of money you should receive a solid good running vehicle! 2 dealers are now telling me that there is nothing they can do! BULLCRAP! I have owned many chevys and this is the worst running one I have ever had! For those of you who are lucky to have a good running one, realize there are many of us out there that have bad ones! as the forums will show!
#10 of 106
fuel gauge and engine hot error by akflyer
Dec 18, 2007 (8:47 pm)
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Just purchased 2008 Z71 Siverado 1500 5.3L 3300 miles both sensor causing engine hot error and fuel sensor back ordered, problem seems to be wide spead and cold related accordin to local dealer in Anchorage
#11 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [cadillac5] by tafid
Dec 20, 2007 (4:17 pm)
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Replying to: cadillac5 (Oct 17, 2007 4:08 pm)

I agree that something is not right. This my experience.
When easing to a stop or after stopping and slowly rolling (by easing off brake, no throttle apply) into my garage, the engine speed will increase surging the vehicle forward. It does not matter if the engine is cold or warm, nor driving for one minute or one hour. The engine speed will increase up to ~1000 rpm or more. The engine speed will surge and slowly come down to ~600 rpm in less than 15 seconds. This problem does not occur all the time, but I can bet on it happening each time I drive.
This condition is known and called normal (by GM) with Silverados with AFM. I tried to get someone at Chevy to see that a vehicle accelerating on its own is not right. No luck. They don't talk to you, they send customer service to deal with you instead.
So I will need to live with the condition and hope the sudden accel does not get someone hurt.
#12 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [tafid] by 1offroader
Dec 26, 2007 (8:36 pm)
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Replying to: tafid (Dec 20, 2007 4:17 pm)

tafid
I have AFM on my 2007 Silv. w/6.0. It doesn't do anything like you describe. In fact, AFM 4 cyl. mode does not even engage at speeds less than about 15 mph. I think it is WAY premature to blame your problem on the AFM system. It could be a malfunctioning engine control module, a sticky throttle body, etc. There are many things it could be besides the AFM. I am in no way downplaying your problem, just pointing out it very well may be unrelated to AFM. Good luck solving the problem, please post when you do. So far at 13K no problems, I like my Silverado. It's not perfect, but what is? It's the best 1/2 ton truck out there now, for a while anyway, at least until the Ford and Dodge re-design in a couple years.
 
1offroader
#13 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [1offroader] by tafid
Jan 01, 2008 (9:03 am)
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Replying to: 1offroader (Dec 26, 2007 8:36 pm)

1offroader
Thanks for the comment. I am not the one who said my sudden accel issues was caused by the active fuel management system. The company (Chevy) told me that the reaction I am getting is normal with all Silverados with AFM. I agree that there seems to be another issue, but no one will listen or acknowledge it. As I was verbally told in the beginning of my attempt to get his resolved, there is no calibration for this issue 'at this time'. So I am stuck with a vehicle not functioning properly. There are no safety concerns and therefore no urgency on their part.
 
tafid
#14 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [tafid] by 1offroader
Jan 01, 2008 (5:39 pm)
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Replying to: tafid (Jan 01, 2008 9:03 am)

tafid
I don't care what the Chevy dealer is telling you, it isn't true. I don't experience any of those symptoms. Nor do most other Silverado owners. The dealer may just be trying to get out of fixing it. Don't allow that to happen, stand your ground and get it fixed.
 
A vehicle surging forward unexpectedly, such as you described in your earlier post, is most certainly a safety issue and you should present it as such.
 
1offroader
#15 of 106
Re: 2007/2008 Sierra Active Fuel Management Problems [santaman58] by natesms
Jan 18, 2008 (9:28 am)
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Replying to: santaman58 (Nov 26, 2007 12:45 pm)

I recently bought a 2008 Max with the 6.0 and I have the same concerns that you posted here. I have a rough idle (it seams low to me to, 450 - 500 rpm when in gear and stopped). The RPM's bounce around a little when you are sitting at a stop light.
 
I also have the same tugging issue when you go up hills. That one really bugs me, you have to give it some gas to get it to downshit to make it stop. There is also no question when AFM is kicking from 4 to 8. You feel it, even at highway speeds.
 
I just got this vehicle so I'm hoping the computer learns over time, but I'm not convinced. I test drove a 5.3 version for 3 days and loved it. Didn't have any of these issues at all. Everything was smooth as could be. When my 6.0 got to the dealer, I hoped in, ran around up the highway and back and bought it because of my fantastic experience with the 5.3. Now that I have it at home I'm really starting to get concerned. Does anyone else have some insight on their experiences? I'm not jumping to conclusions yet as it only has 200 miles on it, but these things have jumped out at me compared to the 120 miles I put on that 5.3.
 
Also, fuel mileage. Anyone able to get anything close to the sticker on the window? I ran 35 miles on flat road at about 60 - 70 mph and averaged 13.4...holy crap!

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