AFM mode issue

2016 Sierra Owner · November 29, 2016

I have a 2011 1500 so my dash doesn't have the screen like that.

What trim level is your truck? I had the V4/V8 on my 2009 SLE Sierra. It was on the fuel economy screen if I'm not mistaken. One of the bottom corners.

AllTerrainX · November 29, 2016

It all depends if the truck is going up a slight hill, the cruise control having to give it a little more gas to keep up to the set speed, etc...sounds normal to me for it to switch back and forth. Unless you are on a flat level road for your whole trip, I wouldn't expect it to stay in v4 mode the whole time.

Slugworth · November 29, 2016

What trim level is your truck? I had the V4/V8 on my 2009 SLE Sierra. It was on the fuel economy screen if I'm not mistaken. One of the bottom corners.

Yes I did find it on that screen.

gSwift · November 29, 2016

I do now!! Sorry bout that. I need to look at the sub forum before I reply...

BTW I cycled through to the fuel efficiency and it tells me what I'm in V4 or V8...

No worries man. Glad you found it anyways.

luapxix · December 4, 2016

It all depends if the truck is going up a slight hill, the cruise control having to give it a little more gas to keep up to the set speed, etc...sounds normal to me for it to switch back and forth. Unless you are on a flat level road for your whole trip, I wouldn't expect it to stay in v4 mode the whole time.

its usually on a straight away on the freeway it seems to only happen when going in the 70mph range its weird ill be in cruise control going 75 v8 mode then drop to 74 and itll go into v4 mode then other times itll just go back and forth flip flop fast.

last truck · December 4, 2016

its usually on a straight away on the freeway it seems to only happen when going in the 70mph range its weird ill be in cruise control going 75 v8 mode then drop to 74 and itll go into v4 mode then other times itll just go back and forth flip flop fast.

at 70 and up the brick in the wind affect comes into play needs more power and CC isn't the best at maintaining a speed without throttle corrections. If it bothers you then turn the CC off

AT/GMC · December 5, 2016

at 70 and up the brick in the wind affect comes into play needs more power and CC isn't the best at maintaining a speed without throttle corrections. If it bothers you then turn the CC off

Or just drive in M5 which eliminates V4. To me V4 is just a selling point. I feel like it doesn't save you that much gas to make a difference.

AllTerrainX · December 5, 2016

Or just drive in M5 which eliminates V4. To me V4 is just a selling point. I feel like it doesn't save you that much gas to make a difference.

You must have the 6 speed? Sometimes I'll be in M7 on the highway 70+mph

AT/GMC · December 5, 2016

You must have the 6 speed? Sometimes I'll be in M7 on the highway 70+mph

Yep, 2014 All Terrain 6 speed. When I'm pulling my flats boat, I use M5 with the cruise control and there is no downshifting at all going up and down the inclines on the highway. If I was cruise in D, downshifts like crazy and constantly switches between V4 and V8. Boat weighs about 1000lbs.

kp52 · December 5, 2016

Both my '15 and '16 do that at 70-75mph, its very noticeable on the '16 because the exhaust chirps when switching to V4 from V8 and its pretty annoying (on my 2nd exhaust in 8K miles)..

I finally broke down and bought a range afm disabler, was going to buy a quiet GM Borla but wasnt too thrilled about spending a grand. Truck feels a lot better all around and the trans (6 speed) acts way less stupid, just like driving in M5. Did take about a 1mpg average hit in the last 1000 miles, worth it me for how much better the truck drives..