Last post on Nov 26, 2013 at 5:54 PM
You are in the Chevrolet Silverado & GMC Sierra
What is this discussion about?
GMC Sierra 1500, Chevrolet Silverado 1500, Fuel System, Truck
#311 of 415 Re: 2008 Silverado 5.3 AFM [string2]
Dec 17, 2012 (5:19 pm)
String also needs to tell you that he didn't need the truck anymore for the primary application he originally purchased it for.
#312 of 415 Re: 2008 Silverado 5.3 AFM [chuck1]
Dec 17, 2012 (6:21 pm)
Do you own a Silverado or Sierra with an AFM engine?
#313 of 415 Re: 2008 Silverado 5.3 AFM [churchy25]
Dec 17, 2012 (6:27 pm)
all I can say, in the words of Blake Shelton(country singer coach on the voice, aka, entertainer of the week), is "dang it". I feel your pain. I've also left GM for another brand - a RAM. Might as well join me and probably 30,000 or 40,000 others in the future according to chucky1. When you add in the cost of engine replacement, a GM truck can't compete with Ford, Toyota or RAM. It is what it is.
#314 of 415 Re: 2008 Silverado 5.3 AFM [sadsilverado]
Dec 17, 2012 (8:16 pm)
I own a 2011-5.3 with the AFM. I am currently on a cross country trip and have driven over 2,500 miles through all kinds of terrain pulling a 5,000pound 28foot travel trailer. The mpg towing has been between 10 and 14 depending on terrain, headwinds, etc. It's probably safe to say that no one here on this board is in the process of using their truck to travel across the country towing a trailer.
I have also driven the vehicle 3 times from So. Cal to Salt Lake City, UT ( and back-non towing) and have achieved 20 mpg consistently with the AFM in 4 cylinder mode. It's great feature.
I am the first to say the 6 speed transmission I S LESS THAN REFINED.
#315 of 415 Re: 2008 "Certified" used GMC Sierra [jswain2]
Dec 18, 2012 (7:20 pm)
Well I ran 2 cans of seafoam with a tank of 93 octane gas. The spark knock stopped, so when the tank was nearly empty, I put 10 gallons of 87 octane in. The spark knock has returned. My problem may be something simple like a partially clogged fuel injector, slightly faulty MAF sensor, eroded spark plug(s), faulty coil pack, etc, etc. I just don't have the time to chase the problem or the money to throw parts at it. The salesman from the dealership did call and ask about how the truck was doing today, but I was working and the call went to voicemail. I will call him back tomorrow and see if they want me to bring it in. What's strange is the new 2012 Silverado I drove with 30 miles on it spark knocked some. Of course the fuel in the tank may have been in there over a year, I guess. I wish the dang check engine light would come on so I'd know where to start looking. The engine also "ticks" at idle with the 87 octane fuel, not as much if at all with 93. Leaning towards a partially plugged injector...but I dunno. Bought this truck because I was tired of working on the 94 chevy and 98 dodge I sold to buy this one. Oh well.
#316 of 415 Re: 2008 "Certified" used GMC Sierra [jswain2]
Dec 22, 2012 (7:20 pm)
Emailed dealer where I bought the truck and told them the fuel treatment that was recommended by their service manager did not work to stop the spark knock or whatever it is. I have yet to see a response. I need to run this fuel out of the truck and try 93 octane again and make sure the noise stops. I'm not 100 percent certain it isn't lifter noise instead of spark knock I have an appointment with another dealer set for 12/27. If they tell me they can't hear the noise or the noise is normal, I'll be trading the truck for another brand. I didn't buy the truck new, but I laid down over $20k cash, and I don't intend to drive it around and listen to it make ticking sounds. It's frustrating because I'm sure I will lose money trading it, even though I've not had it long enough to even receive the title from the state. Started hearing the noise before I even got a tag on it. Sheesh! What a drag. I usually only trade vehicles once every 8 or 10 years. I try to get 200k miles out of them. I seriously doubt this one will make it that far since it only has 54k now. If I don't get it resolved the 27th, I'm f150 shopping. Ugh...I dread dealing with trading again.
#317 of 415 Re: 2008 "Certified" used GMC Sierra [jswain2]
Dec 23, 2012 (11:38 am)
First of all-I am sorry for all your troubles. There are a couple of things to learn from this exercise in frustration.
1) A USED VEHICLE IS A USED VEHICLE FOR A REASON. Sometimes the owner gets tired of it, or doesn't need that type of vehicle anymore, OR there is something wrong with the vehicle he is trading in and wants to get rid of it. Clearly, the last statement is applicable in your situation.
2) "Certified" from any dealer or manufacturer is meaningless. It's still makes sense to have the vehicle checked out PRIOR to purchase by your own mechanic. It's called BUYER BEWARE!
I would explain very clearly to the selling dealer that you wish for them to take back the truck ( at full purchase price) and put you in to another truck. If they refuse, explain to them you will plaster their name on every Internet site you can find to explain what happen to you. Be careful not to be slanderous,as they can sue you. Just explain YOUR CIRCUMSTANCES and that will be enough to keep people away or have second thoughts about buying from them.
#318 of 415 Re: 2008 "Certified" used GMC Sierra [chuck1919]
Dec 23, 2012 (9:46 pm)
I appreciate your input, and may indeed follow your advice on trying to trade with the dealer. However, by your reasoning, the used vehicle I would be trading mine for would also be used for a reason, right? I checked the truck out the best I could. Drove it quite a while, even crawled under it to look for leaks. I doubt a mechanic checking it out would have noticed anything. I do all mechanical work on my vehicles myself if I can. I can and will do anything short of transmission work or internal engine work. It pretty much only does it at full operating temp in V4 mode, which it doesn't stay in very long unless you try to make it. Hard to catch that right off. At this point I'm trying different gas stations and octanes to see if anything changes. Also going to let the other dealership have a look at it the 27nth and go from there.
BTW, one owner truck and I called the previous owner who said he never had any issues but admitted his hearing wasn't the best (older gent).
I'm sure you're a nice enough guy, but for some reason you seem to want to put blame on the owner, not the vehicle, manufacturer, or dealership. . I'm well aware that buying a used vehicle is a gamble, but a certified used vehicle comes with a warranty, so if something's not right, the dealership needs to fix it in a hurry. No questions asked. Certified should mean....certified.
Honestly, if I had bought the truck new, I'd have quite a bit more money invested, so maybe that would have been the bigger gamble. The reason I don't buy new is I can't afford it unless I finance it. And to me (most will disagree), financing a new vehicle is just throwing money away since they drop in value so much the first few years / miles. Take your truck, for instance. How many miles on it? If it starts having problems in 4 or 5 years, regardless of the mileage, you've lost quite a bit of money if you try to sell or trade it. I guess if your truck starts to make the racket mine does at 50k miles the argument could be made that you didn't do enough research on the AFM system before you made your purchase. BUYER BEWARE, right?
#319 of 415 Re: 2008 "Certified" used GMC Sierra [jswain2]
Dec 26, 2012 (8:42 am)
Keep us posted on how your appointment goes tomorrow! If you would like for us to check into anything further for you, please contact us at socialmediagm.com (include your name, contact information, the last 8 digits of your VIN, and a summary of the situation).
Sarah, GM Customer Service
#320 of 415 Re: 2008 "Certified" used GMC Sierra [gmcustsvc]
Dec 30, 2012 (9:56 pm)
Well, the visit to the dealership went about as expected. The service manager got in and we drove for about 5 minutes (with no scan tool). The service guy said he didn't hear anything. Which isn't surprising, I didn't hear it that often in the 5 minute drive either. It doesn't make the noise constantly, so no surprise it wasn't heard by him in 5 minutes. He did say the AFM motors did make noises different to a regular engine. I asked him why. He said he didn't know, could be partially clogging oil passages....which didn't help my feelings much. Lol.
The dealership where I bought it will trade on another truck, but not at the value I purchased this one for. I asked the salesman why I had to lose money trading it back to them. He told me they expected 1500 dollars in repairs and were allowing for that. Total BS as they will no doubt sell it as is again. He offered to trade my truck for a 2012 new truck similar to mine with the smaller V8 (no afm) and less options for an additional 9k. I told him I'd do it for 5k, no additional fees, otherwise I'm done with them. He said hed let me know, but no word yet. Also have a possible 2wd drive Tundra I may could trade even for. If the Tundra or the 2012 base model don't pan out, I suppose I will run higher octane fuel to mask the problem and trade this truck later. A bit tired of salesmen right now.
Sarah, thanks for the interest, but what can you really do? Let's assume for now that I am correct and the engine has a random misfire at times due to a weak lifter or some other engine component. Let's assume the misfire could be seen if a technician drove the truck with a scan tool hooked up to the OBD port. Is GM going to put new lifters in my truck because of a missfire that has not set an OBDIII code yet? I doubt it. The truck operates well now, and a lot of people wouldn't notice the noise. The problem for me is the noise is probably caused by a mechanical fault that will reduce the life of the engine. So what could be done? Extend the warranty? Regardless, I will be e-mailing you the requested info anyway. I doubt much will come of it, but at least I will have a record of it.