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Impala SS - Question about the AFM system

18 messages,  Last post on Jun 26, 2007 at 1:33 PM

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What is this discussion about? Chevrolet Impala, Chevrolet, Sedan

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#1 of 18 Impala SS - Question about the AFM system by jpstax1

May 17, 2007 (9:26 pm)

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.

#2 of 18 Re: Impala SS - Question about the AFM system [jpstax1] by quietpro

May 18, 2007 (6:13 am)

Replying to: jpstax1 (May 17, 2007 9:26 pm)
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.

#3 of 18 Re: Impala SS - Question about the AFM system [quietpro] by 303ss

May 18, 2007 (7:29 am)

Replying to: quietpro (May 18, 2007 6:13 am)
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.

#4 of 18 Re: Impala SS - Question about the AFM system [303ss] by quietpro

May 18, 2007 (1:02 pm)

Replying to: 303ss (May 18, 2007 7:29 am)
303ss,
  Were you achieving the high FE quoted in the other thread with premium fuel?

#6 of 18 RE:IMPALA SS- Questions about AFM by chriseh

May 30, 2007 (8:39 pm)

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.

#7 of 18 RE:IMPALA SS- Questions about AFM [chriseh] by quietpro

Jun 02, 2007 (6:17 pm)

Replying to: chriseh (May 30, 2007 8:39 pm)
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.

#8 of 18 epa for ss Impala so far by teresabutler89

Jun 04, 2007 (8:58 am)

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!

#9 of 18 Re: epa for ss Impala so far [teresabutler89] by nosirrahg

Jun 04, 2007 (10:39 am)

Replying to: teresabutler89 (Jun 04, 2007 8:58 am)
www.fueleconomy.gov 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.

#10 of 18 Re: epa for ss Impala so far [teresabutler89] by jpstax1

Jun 04, 2007 (8:33 pm)

Replying to: teresabutler89 (Jun 04, 2007 8:58 am)
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.

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