Edmunds.com | Inside Line | Auto Observer Your Account | Help | Directory
You are here:
![[F]](http://a332.g.akamai.net/f/332/936/12h/www.edmunds.com/media/townhall/webxicons/site.gif){kind=small}
Forums
Pickups Chevrolet Silverado & GMC Sierra Chevy Silverado and GMC Sierra Real World MPG Numbers
116 messages, Last post on Aug 23, 2009 at 6:14 PM
You are in the Chevrolet Silverado & GMC Sierra Forum. Your Host is kcram
Yes, Ethanol does drop the mileage that you get. I live up in North Dakota and here E85 is selling for $2.54 and regular 87 Octane gas is at $3.09. With that spread you are a little better off running the ethanol. I have figured that on my 07 silverado I need ethanol to be at least $.50/gallon cheaper to make it even out. After that it works out, too bad that there isnt something that can be added to ethanol to bump the energy content.
|
|
|
Replying to: nascar57 (Jul 24, 2007 6:48 am) |
|
|
I've been searching for 4.8l/3.23 mileage and it seems like a few years ago seeing 17-20 real world mpg (mixed) was the norm. Now the NBS seems to get 13-16 mpg? What changed on the regular cab to drop the mileage? I'm aware the new EPA ratings changed, but again I'm looking at owner's report mpg. |
|
|
Getting the rated 18 city 22 highway with my Canyon, I was looking forward to getting similar numbers with a 2007 V8 Sierra thanks to the "advertised" active fuel management. So, since no one locally had a regular cab 4x4, I just drove 900 miles round trip to take advantage of the current rebate to "buy" my new Sierra. After getting there, the wife and I naturally went for a long test drive and I placed the dash display in AFM readout mode. Once the vehicle got past about 62 MPH, AFM never engaged once. Never leaving V8 mode, the instantaneous mileage varied from 13-19mpg with the vehicle on cruise control about 68mph. Now, if you drop below about 62MPH, then the AFM would engage and you would see a noticeable instantaneous mpg difference when it would enter V4. Question: How many people cruise down the highway below 62mph?  The sales person called his GM certified tech who responded by saying especially the 4x4s require all 8 cylinders above about that speed. Sadly, I drove back home with my Canyon but at least I learned of this during the test drive instead of after the purchase. I personally find this to be false or certainly misleading advertising. My '99 Sierra 5.3 V8 would get 16 city 20 highway without AFM. The 2007 ranging between 13 and 19 mpg on cruise control at 68mph, there's no way it's ever going to get 20 highway without a BIG asterisk *Below 62mph only. And this was just a regular cab version that's 600 pounds lighter than the extended cab and 700 pounds lighter than the crew. I can't imagine what kind of mileage they're going to get. Any chance GM would refund my trip expenses  ? Thought those of you in the market should keep this in mind so you don't learn the hard way. I've seen others on this forum and elsewhere complaining about horrible mileage and just attributed it to lead-foot syndrome. I think they're just unfortunately experiencing in ownership what I saw during my test drive. When you're on cruise control, it's hard to blame your right foot. 
|
|
|
|
|
Replying to: olz442 (Aug 18, 2007 7:42 pm)
|
|
| I am looking at a 2008 4x2 Silverado with the 5.3 engine. Should I get the iron block version or the flex fuel one? Will there be a difference in MPG or engine life or performance? Thanks... | |
|
Replying to: harrybackman (Sep 04, 2007 7:57 pm)  70MPH and it's only rated at 22 HW.
|
|
|
|
|
Replying to: olz442 (Sep 11, 2007 10:09 pm) The truck frequently goes into afm mode below 70 mph, and occasionally between 70-75 mph. 74-75 mph seems to be the cutoff where the afm won't engage any more. I think it would easily meet (or exceed) the 19 mpg highway rating if I stayed at 65. BTW my trip was mostly in cruise control. That is key to getting good mpg. The trip also included about 10% mountain driving, but it is interstate thru those mtns. and the speeds were about 70 mph. In lousy stop-n-go Los Angeles traffic I get 14-15, which is as good as I can expect. AFM really works. As long as it is reliable, I am sold on it. I recently bought a pop-up trailer, approx. 2400 lbs. empty. I am curious what my mpg will be while towing. Will post when I have some data. 1offroader
|
|
|
Replying to: 1offroader (Sep 12, 2007 7:12 pm) The bottom line is that there will always be some flat driving, downhill time, tail winds, etc where the AFM will engage and save fuel. I've actually seen it engage while pulling my 5000# Camper. There will also be times when you'll never see AFM engage - High speed highway driving, hot day - AC running all the time, head wind etc. Still, I'm sold on the technology. One potential problem is that the system does not rotate the cylinders that it disengages... i.e. the same 4 cylinders always turn off. Over time, will the uneven wear cause problems? With the tight tolerances and better materials used in these new engines, it may never be an issue, but my instincts lead me to believe that it could be.... Time will tell
|
|
|
|
|
Replying to: summitx02 (Sep 13, 2007 8:37 am) The issue of uneven cylinder wear should not be a problem. The pistons in those cylinders are still moving up and down - they have to, they're connected to the crank shaft. They just aren't drawing in fuel and firing because the valves are de-activated. I wouldn't worry about uneven wear, that's not going to be a problem IMO. 1offroader
|
|
You are here:
Forums
Pickups Chevrolet Silverado & GMC Sierra Chevy Silverado and GMC Sierra Real World MPG Numbers
New? Join Now!
Forum Tools
Search Forums
Browse by Vehicle
2010 Chevrolet Silverado 1500
2004 Chevrolet Silverado 2500
2006 Chevrolet Silverado 3500
2010 GMC Sierra 1500
2004 GMC Sierra 2500
2006 GMC Sierra 3500
Browse by Board
Browse by Topic
Today's Chats
