AFM for 08 G8 GT

[SpiderJedi]

I've installed a set of axelbacks over the weekend and I love the sound, but there are times when on highway, or about 1800-2000 RPM when the drone is a little loud inside. Anyway, I have a Cortex and can turn off the AFM, but have not done so yet. I don't fully understand what it does for the L76 in the 08 G8 GTs. I thought that the 08 did not have the enging displacement when it shuts down 4 CYL in highway driving.

Long to short -- What's the AFM do for me? What do I loose by turning it off?


Thanks!!!

[Devilish34]

Mpg (2-3)

[zepcom]

afaik - all model years G8 GT's with the L76 engine (but not the V6 sedan OR the GXP with the LS3) have AFM that DOES de-activate the cylinders.

I'd suggest that you flash it to disabled and drive around a bit. If that fixed the problem, then you found that AFM has been enabled on your 08 all along.

Another idea is to start up the car in engineering mode... hold down the left side steering wheel button (the enter key one) while cranking the car, and scroll down to "active fuel management" choice near the bottom .... then drive around.

When it says "Half Active" then that's AFM mode enabled ... if this corresponds to when you hear the unwanted drone, then you've found the problem. When you gas it it should go into "full active" which is all 8 cylinders.

hope this helps...

--zepcom

[Devilish34]

Or put it in manual...this will disable the AFM

[avintegrator]

I've got the same axle backs and I drive mainly in manual now, its a whole lot more funb! My only problem is switching between my wifes mazda 6 and my G8 is the shifters are bass ackwards from each other, it has caused a couple of whoops moments. Anyway if disabeling AFM helps the issue then I may do it also. Can you say guinea pig ;)
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[johnh]

I've tested AFM 3-5 mpg on the highway. Don't expect to ever see over 22 really with it turned off.