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Hey everyone. I just recently joined the forum, but have always read through numerous posts and appreciate everyone that is willing to help out.

In March of this year I purchased a brand new 2011 Silverado 1500 ext cab with the 5.3l. It has the flex fuel option as well as active fuel management. The looks of the truck are fantastic and I really enjoy the styling. Up until recently I've enjoyed my new truck, but this AFM system makes me want to get rid of it.

I used to own a 2005 silverado with the 5.3l and it ran fantastic. Plenty of power and decent gas mileage. With this new truck I'm seeing poor gas mileage ~15mpg with the AFM system. The system is very annoying and its not "seemless" by any means. Around town it's absolutely horrible. Trying to climb hills or even red light to red light it wants to jump to this AFM V4 mode. It has no power and it seems like this truck (6 speed AUTO) is constantly searching for the right gear.

I've been a diehard GM fan since day one, but this truck is making me think otherwise. I know you can purchase tuners to remove the AFM but that voids the warranty. I've called the dealer and they claim AFM can't be turned off.

Spending $30k plus for a vehicle that runs like this is just ridiculous. I'm at a loss here and just dont know what to say...
 

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Have you had a dealer look at it? We have a 2008 TrailBlazer with the LH6 (5.3l AFM) and haven't had any issues. I really can't tell when it switches modes.
 

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I have the exact same model and year as you and yes the AFM is very very annoying. All i do when i round a corner and i can feel or hear that its in V4 ismode i just punch it a little and it comes out. It bugs me but theres nothin we can do about it. All the berry pickers get mad about burning gas thats all it s
 

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Discussion Starter #4
Have you had a dealer look at it? We have a 2008 TrailBlazer with the LH6 (5.3l AFM) and haven't had any issues. I really can't tell when it switches modes.

I've considered that but the problem is if there isn't a service light I doubt they'll do anything. It's extremely annoying. Guess I could make an appointment though.

---------- Post added at 12:41 PM ---------- Previous post was at 12:39 PM ----------

I have the exact same model and year as you and yes the AFM is very very annoying. All i do when i round a corner and i can feel or hear that its in V4 ismode i just punch it a little and it comes out. It bugs me but theres nothin we can do about it. All the berry pickers get mad about burning gas thats all it s
I agree. But they claim it should be seemless. One thing i've noticed is when I first pull out in the morning. If I go real slow there is some clicking going on in the gas pedal. It's faint but its almost as if something is being reset. Do you have this issue? Also, sometimes it gets stuck in V4 and I really have to goose the pedal to get it back to v8.
 

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You can remove the AFM with a Diablo Triniy or Preditor, just make sure you go back to stock settings before you go in for warranty work and leave the Diablo home ( we had customers leave there Diablos on the front seat when having warranty work done, dumb as***).
 

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I have bought my first ever new GM product a 2011 GMC Sierra with same setup 5.3 with AFM I am coming from a long line of Fords and Dodge trucks last was a 2006 F150 FX4 with 5.4l with 12-13 mpg so the 15.2 avg (in town) is some what better and don't have any issues with drives in town no hesitation truck has maybe better acceleration than last Ford. I'am running a Volant CAI and do notice a downshift sound when cruising sometimes .
 

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Hey everyone. I just recently joined the forum, but have always read through numerous posts and appreciate everyone that is willing to help out.

In March of this year I purchased a brand new 2011 Silverado 1500 ext cab with the 5.3l. It has the flex fuel option as well as active fuel management. The looks of the truck are fantastic and I really enjoy the styling. Up until recently I've enjoyed my new truck, but this AFM system makes me want to get rid of it.

Spending $30k plus for a vehicle that runs like this is just ridiculous. I'm at a loss here and just dont know what to say...
I would also recommend that you contact your local dealership for a diagnosis. Please feel free to keep me posted. Thank you.

Tricia, GM Customer Service.
 

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Hello everyone, Newbe here. If just got a 2011 Silverado Ext 4X4 Z71 with the 18" wheels on July 4. And I really it like. I only have 1500 miles so far and the AFM system works great. In fact everything works great so far....Pulls my 6,000 camper with ease. Had it up on the Beach at Delaware National Seashore State Park (Surf Fishing ) and truck did just fine in the sand, but my old 2002 Silverado also did good on the beach too. The one thing I don't miss that my old truck had was listening to piston slap every morning for nine years.
Dave
 

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AFM SUCKS!!! I got a hypertech programmer thinking i would be able to disable it. Nope it didnt support my engine or something stupid. Its ridiculous. I had a 2000 5.3 and ran a y pipe and aem intake..got 17 mpg with it. Get a 08 and now i get 11-13..lol thats after my lift..prior i was making 16 around town. Im looking into blackbearperformance.com they claim to be able to disable the afm and I had trouble after you change tire size with a hypertech (or alot of other programmers) your abs light comes on after you drive a couple miles. So just keep an eye out and watch what programmer you use. Double check and Id even call them and double check with a live person that it will do what you want. Good Luck
 

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Discussion Starter #10
BigMike, I have the exact same problem with the gas pedal clicking. Did you ever take it to the dealership? I called the dealership yesterday, well actually called 2 of them to get warranty work and no one has returned my calls. Fancy that.

I'm hoping they replace the gas pedal or do something. My wife and I just purchased a 2007 tahoe with AFM and the V8 to V4 transition is absolutely seemless. I agree with you that sometimes I have to goose the pedal in my silverado just to get the damn thing to transition back to v8 mode.

---------- Post added at 07:22 AM ---------- Previous post was at 07:20 AM ----------

Disabling the AFM will void the warranty. Trust me if GM would disable the AFM I would gladly wait in line.

The thing that worries me is taking it to the dealership. I'm sure without a SES light they will just ignore it. Dealerships have done it in the past....part of the reason I hate going. I can't imagine the gas pedal clicking normal. Our tahoe doesnt do it at all. It is seemless.
 

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I would like to look into this further for you. Please feel free to contact me privately with more information. It may also be helpful to include your VIN and contact information. Thank you.

Tricia, GM Customer Service.
 

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you want afm disabled? youll have to pay but it can be done. Check out blackbearperformance.com they can reprogram your truck anyway you would like. ive got my autocal and about to record data so i can get my custom tune done.
 

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I have a new 2011 v8 5.3l with afm, same as you and I find that it is seamless. I see it go into v4 and I cant tell unless im looking at instant fuel economy and as soon as i touch the gas it seamlessly goes back to v8, I really cant tell its there, i love that it goes into v4 mode and saves me gas. I actually have to back off the pedal many times as the truck has so much power. I have only 600 miles on my truck but last tank I got 15.8 mpg all city driving, for a big v8 not bad, its almost two mpg better than i was getting with my 2001 jimmy in town, although i had 150,000 on that before getting this truck. which I love by the way!
 

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My 2011 5.3 also runs great with the afm, I also find it is seamless. I'm getting great fuel mileage around town, plenty of power, the quality & performance of the truck is almost to good to be true.
Dave
2011 Silverado 5.3 Z71 Ext, 18" wheels, Leer Hard body tonneau cover
 

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I have a 2011 Silverado, 5.3, 3.08 rear, 2WD. I can barely feel the transition from V8 to V4 and back. It is virtually seamless but noticeable none the less. I do not find it objectionable in the least and am glad it is there.

My only comment is how little it stays in V4 mode. At highway speeds, 55-65, on flat terrain (I live in coastal NC), it goes into V4 mode rarely. Frankly, would like to see it do so more thinking it would help the mileage. Wonder if a lower rear end (3.42) would have given better mileage? Only have a couple of thousand miles on the truck and averaging around 17mpg. Im satisfied but hope to see a little better as the truck gets some more miles on it.
 

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Discussion Starter #16
Just wanted to provide an update to my dilemma. For those of you that the AFM is working flawlessly or that like it - congrats. I mean the idea of AFM is actually pretty decent and it must be nice that it actually works on some of the trucks.

With that being said I'm not as lucky. My AFM just doesnt work right at all. Truck is constantly shifting and always powerless. When the AFM kicks in it feels like it's completely gutless. I guess my biggest complaint is that it gets stuck in 4 cylinder mode and I can always feel it kick in to V8 mode. Almost makes me want to go to a different brand.

Took it in to the dealership and was not suprised. They didnt find anything wrong. Gotta love it.

All in all not happy at all with my Silverado.
 

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94blackcamaroz28,

I have the same thing happening with my truck. I can feel it changing from V8 to V4 mode at highway speeds as if the cruise is speeding up and down every 5 seconds. In town it isn't as bad but I can feel the vibration especially when I slow down and speed up. It's like it doesn't want to go back into V8 mode right away and struggles for about a second before it'll change back into V8. I too asked the dealership about it and got the same response as you. The dealer admitted that they have had many complaints about this. I've personally talked to a dozen or so people with 2010 and 2011 pickups that have the same complaint. A buddy of mine bought a programmer and shut it off in his truck and he is enjoying his truck now. He says the gas mileage is any worse and it's not annoying any more. He said it cost about $300 for the programmer. I'm thinking of doing the same thing unless GM comes out with a fix, but I doubt they will.

I though I'd post to let you know that you aren't alone.
 

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Well folks mine is a 2010 and I have been back and forth with the dealer and their " we are unable to duplicate your concerns" . I get a growling sound when mine goes to V4. Also going downhill or several miles with the cruise set it never goes to V4. In the morning my truck idles roughly and dealer even felt the same thing but no fix.
 

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AMF SUCKS ... I have a 2008 5.3 amf it started using oil at around 27000 miles and still uses 1 quart in 1000 miles. They tell you that they have to do an oil consumtion test then they over fill the oil. then sudjests putting a deflector in the oil pan(hahahah) like thats going to fix it they just try to prolong the problem till you will give up.. just like i did got tired of the run around....I fixed my problem i traded it off.
 
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