Impala SS - Question about the AFM system

jpstax1jpstax1 Member Posts: 197
edited March 2014 in Chevrolet
I'm considering buying an '07 Impala SS, but have a question about the 5.3 V8's active fuel management (aka DOD). Has anyone ever had a problem with this system? If it were to somehow get stuck in 4 cylinder mode, would the car still be driveable, or would I be stranded? Thanks.


  • quietproquietpro Member Posts: 702
    No problems with the system but if it did fail, I would safely assume it would stick in 8 cylinder mode since it has to activate to engage into 4 cylinder mode....for what it's worth. I love it. :)
  • 303ss303ss Member Posts: 5
    To have a 4 cyl with gas prices the way they are, but the extra 8 cyl. power when you want it is great! I think GM did a great job on this DOD system.
  • quietproquietpro Member Posts: 702
    Were you achieving the high FE quoted in the other thread with premium fuel?
  • chrisehchriseh Member Posts: 2
    Dose the AFM REALLY improve the Impala's MPG (significantly) over the EPA (which is a government estimate based on the engine, whether v4, v6, v8, etc, and not based on car performance??? I am interested in what kind of mileage people are REALLY getting with the 3.5 liter V6 engine with AFM.
  • quietproquietpro Member Posts: 702
    The 3.5L engine doesn't have an AFM system, called DOD by GM. The 3.9L and 5.3L engines have DOD and fuel mileage is improved during light to moderate acceleration or cruising at legal highway speeds. At higher speeds or during hard acceleration, DOD isn't engaged so there is no advantage.
  • teresabutler89teresabutler89 Member Posts: 34
    We just got a 07 . V8 Impala. We've had it for a little over a week so far. The MPG for the highway so far as been around 20.5 mpg. Have been told from dealers , service manager that it needs to be broke in, around 10,000 miles it will be broke in & the MPG is supposed to get better. But was also told that the government is changing those MPG stickers from the current stickers , so they will not show , oke for example showed. 20 mpg for city, 27 for highway. Well after purchasing this car with this info. the gov. is going to change the window stickers for the 2007, & the car we currently bought, will have the city mpg lowered as well as the highway MPG. SO far we are concerned , & wish we would have just went for the IMpala LTZ or the LT with a V6. We just traded in a 06 Malibu that was getting close to 30 mpg. The only reason we went for the SS is because the window stickers MPG showed the V8 getting the highway MPG of 27, which is pretty close to the 06 malibu we had. Kind of missing the Malibu now! :cry:
  • nosirrahgnosirrahg Member Posts: 872 has listings now based on the "new and improved" EPA figures; the 2007 Impalas break out as follows:

    3.5l 6-cylinder 18 city/28 highway
    3.9l 6-cylinder 18 city/26 highway
    5.3l 8-cylinder 16 city/24 highway

    FWIW my 2000 Impala (3.8l V6) was originally rated at 20 city/29 highway; now rates 17 city/27 highway with the new figures. In the course of 107k miles, I've NEVER had a tank of gas average less than 18 MPG that I recall, and back when we used it on long trips I'd routinely get 30 MPG (once got 34 MPG, but that was at 60 MPH in the flat Delta of Arkansas, without the AC running). My overall average for the life of the car is around 22.5 MPG, so hopefully the new figures are more "worst case scenario" as opposed to what you'll typically encounter. But odds are you'll be lucky to see 25 MPG on the highway, and probably won't come close to 30.
  • jpstax1jpstax1 Member Posts: 197
    I've read and heard the same thing from Chevy and Pontiac sales reps. Both said their mechanics told them the 5.3 V-8 engine's mileage improves with age. Why, they didn't know. My guess is that the pistons have to work harder because of tighter wall clearances. After awhile they loosen up a bit.
  • chrisehchriseh Member Posts: 2
    Thanks to all for the personal experiences, informations and clarifications...appreciate it. chriseh
  • teresabutler89teresabutler89 Member Posts: 34
    Thanks I read my sticker that came w/our car, & checked that website out yesterday , after our selling service manager mentioned the new updated MPG window stickers.

    Sure wish they'd updated the Darn window stickers sooner, had the window sticker been the new updated sticker showing the more accurate MPG , we would not have purchased this SS model. But what can we do now, short from selling the darn thing & buying the V6?

    ANyone know of a good website that gives the accurate up to date Resale value of the Impala SS for the 2007 year yet. I check couple days ago & KBB only has the LT & the LTZ values , but for some reason they do not have the used car value for the Impala SS 07.

    You think its the typical w/Chevy, it depricated hugely after we drove it off the dealers lot on our first day of ownership? That's another thing w/these cars, the do not hold their value's.
  • teresabutler89teresabutler89 Member Posts: 34
    oops , i guess I will anwser my own ?. This website edmunds
    gave me a figure of private party value. so my car has already depricated $3200.00 in its first week of ownership! That is horrible! :mad:
  • nosirrahgnosirrahg Member Posts: 872
    Go back to the dealer and see if they'll let you trade the car in on an LT. I bet they'd work with you, especially since it's only been a week or so since you bought the car. Also, I know here there's a "cooling off" law that gives you something like three days to back out of a major purchase like a car with no penalties. You're probably beyond that time window at this point, but I bet if you approached the dealer honestly they'd work with you; especially since the new fuel economy figures just came out.
  • quietproquietpro Member Posts: 702
    I can honestly say I've never done that bad on fuel in my '06 SS and I monitor my fuel mileage religiously...from day one. My worst fuel mileage was on the first tank...highway mileage (of course not recommended) and it was 24.6 mpg. I have ranged between just under 25 to just under 27 ever since on the highway. The lowest mileage I ever got was once when I idled for over an hour and that tank got me 14 mpg. Otherwise, the lowest has been 16 mpg but I average no lower than 18 mpg city.

    I would give your SS a chance. The money you're going to lose in a trade will take a long time to make up in fuel costs. It may seem like a lot of money but do the math based on a car that gets a few more miles per gallon and it will take a long time to make up a few thousand dollars. The only way it it could ever make sense would possibly be with a 40 mpg car and $4/gallon gas...but then you are in a tiny little car and you don't have that sweet sounding V-8. :)
  • teresabutler89teresabutler89 Member Posts: 34
    well thought I'd update how the 07 SS Impala's MPG's been doing on the HWY. NOt any better, actual gotten worse! I'm getting about 19.8 MPG's on the HWY. THe cars starting to have idle issues, when stopped at a stop light w/the AC running. It's sounded like it's wanted to stall & I could even feel it acting like it was going to stall.

    I've called the dealership again complaining. They dealerships looked the car over once & could not find anything wrong w/it. I've asked them to work something out on a New 08 Impala LT V6/3.5L. I a little sad though because I'm going to miss the dual exhaust sound, & I liked the fancy rims the SS has. I thought about the LTZ, because they have sharp rims, but I'm wondering if I'll loose more on the HWY MPG?
  • 442rich442rich Member Posts: 1
    Hello All ,
    New ss 07 took on trip to atlanta and back starting at 600 miles on car and the highway mpg on the leg back with 2000 miles on the clock was 27.o and that was at high speeds 80 mph air on hill and dale . I have the k+n air filter and changed the oil to mobile 1 before the trip . Also new york has the oxy gas like california and the car gets 2 mpg worse on it then the good old gas that you can buy in georga and south carolina . Did cover slightly over 400 miles on a tank with the southern gas .
  • teresabutler89teresabutler89 Member Posts: 34
    Was not able to work anything out w/dealership, wanted us to trade straight across into a cheaper model LT, but we'd be even farther upside down if we did that so we turned them down. I asked them to buy the car but, they declined stating they had too much inventory & didn't want to purchase any more cars at the time.

    Now have to take car back in to shop , due to some idle problems when stopped at stop lights while AC is running, Car acts as if it's close to stalling at times. ALso car has had a strange shifting yesterday after slowing down quickly due to traffice & then upon acceraltion acted as if the car didn't want to go. I thought I was going to get rear ended.
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