AFM issue

slimjim2525 · October 17, 2012

When my AFM kicks to 4 cylinder mode, I get a vibration in the motor which can be felt in the gas pedal. I thought I saw on here before that this is a known issue and a fix with some programming. I can't find where I saw it though. I have an appointment at the dealer for Friday to look into this. Can someone please post if there is a bulletin for this fix. Thanks in adavance.

Sir Dan · October 17, 2012

Good luck... My dealer told me it was normal. Although, my truck did the strange vibration from mile 1 which is why I have AFM turned off with a Predator. If your vibration just showed up maybe they can dig into it further. You might have a lifter going bad or something. Are you burning oil?

slimjim2525 · October 17, 2012

No burning oil.

oldmann · October 17, 2012

Check to see is a wire loom is too close to the engine oil dipstick tube.

slimjim2525 · October 17, 2012

Check to see is a wire loom is too close to the engine oil dipstick tube.

I'm not following you.

oldmann · October 17, 2012

Sometimes there is a rubbing issue there when the engine go into 4 cylinders. It just runs different when on fewer cylinders.

slimjim2525 · October 17, 2012

Sometimes there is a rubbing issue there when the engine go into 4 cylinders. It just runs different when on fewer cylinders.

No issues there.

JrocK817 · October 18, 2012

I posted something about that a few months back. I am having the same issue.

The dealer told me that there was a new program bulletin that came out about the AFM and that it should take care of the problem. WRONG.. turns out the guy i was talking to was new and had no idea what he was talking about. The said bulletin just added the 2012 model silverado / tahoe to the 07-11 list. All it did was explain how AFM worked and that there would be a slight change in the way the truck sounded while switching back and forth.

I tried to explain the vibration to them and they said it was normal. To me, i think AFM kicks on way too much. Stop and go traffic it switches back and forth unless i put more into the pedal.

I plan to deal with it until next year. As soon as Black Bear comes close enough for a live tune a road trip will be in order.

j-ten-ner · October 18, 2012

...As soon as Black Bear comes close enough for a live tune a road trip will be in order. ...

1+

Hope they will be close to Vancouver some day soon.

so long

j-ten-ner

slimjim2525 · October 23, 2012

I posted something about that a few months back. I am having the same issue.

The dealer told me that there was a new program bulletin that came out about the AFM and that it should take care of the problem. WRONG.. turns out the guy i was talking to was new and had no idea what he was talking about. The said bulletin just added the 2012 model silverado / tahoe to the 07-11 list. All it did was explain how AFM worked and that there would be a slight change in the way the truck sounded while switching back and forth.

I tried to explain the vibration to them and they said it was normal. To me, i think AFM kicks on way too much. Stop and go traffic it switches back and forth unless i put more into the pedal.

I plan to deal with it until next year. As soon as Black Bear comes close enough for a live tune a road trip will be in order.

I got the truck back. Dealer told me there was a transmission programming issue. They did a programming update for the tranny and now my vibration is gone.

Heysdad · October 25, 2012

My AFM kicks in and out and even with my Flowmaster 40's and duals out the back, I can hear the change in tone, but no vibration at all. Don't let them tell you it's normal...It's not.

Tell them you want to testdrive a new truck with AFM. See if it does it. If it doesn't and it's supppose to be normal as they say, and the new truck doesn't do it there must be something wrong with the new truck...Right? That should get them thinking.....If it was normal they would all do it.

JrocK817 · October 25, 2012

I posted something about that a few months back. I am having the same issue.

The dealer told me that there was a new program bulletin that came out about the AFM and that it should take care of the problem. WRONG.. turns out the guy i was talking to was new and had no idea what he was talking about. The said bulletin just added the 2012 model silverado / tahoe to the 07-11 list. All it did was explain how AFM worked and that there would be a slight change in the way the truck sounded while switching back and forth.

I tried to explain the vibration to them and they said it was normal. To me, i think AFM kicks on way too much. Stop and go traffic it switches back and forth unless i put more into the pedal.

I plan to deal with it until next year. As soon as Black Bear comes close enough for a live tune a road trip will be in order.

I got the truck back. Dealer told me there was a transmission programming issue. They did a programming update for the tranny and now my vibration is gone.

Awesome! Any chance you can post up the problem description off of your invoice?