AFM/DOD Questions

Re your original problem, this is a common thing. I think GM wants them to do some elaborate test for engine mounts. Mine has a slight vibration at idle, but it only idles at 500 rpm. That is awfully low. Bring it up to 600/650 rpm and the vibration goes away. I think a tune can adjust that.....

vcode said:

Re your original problem, this is a common thing. I think GM wants them to do some elaborate test for engine mounts.
Mine has a slight vibration at idle, but it only idles at 500RpM. That is awfully low. Bring it up to 600/650 rpm and the vibration goes away.
A tune can adjust that.

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Damn skippy, a THOROUGH tune can adjust that. Not a plug-in, or a handheld / canned tuna.
Remember that, especially before the engine stop-start feature, GM has always been trying to improve their CAFE MpG scores.
GM literally cannot afford to raise idle from 525RpM to 650RpM.
No individual driver owner will notice the ever-so-slight fuel consumption increase that goes with raising idle from 525RpM to 650RpM.

For your original issue…it could be several things…with that many miles the very first thing I would do is clean your throttle body. I cleaned mine at 140K miles and I could not believe the improvement it made!…smoothed out the idle and a slight stumble off idle. Many videos on YouTube detailing the process using a good throttle body spray cleaner.

I also recently got a Diablo Intune I3 Platinum tuner for my 16 Denali XL w 6.2 to permanently turn off the AFM (previously used a Range device)…but the ability to bump idle rpm, throttle response etc makes a big difference in overall driving experience. I am looking now to have a full custom tune done by Diablew.

Gearz said:

I live in NH and if I installed a tune that disabled AFM or DOD it would not pass emissions because it's looking for those engine parameters and the truck would fail. I called Diablo tuners and they couldn't answer my questions if a tune would affect OBD2 for state inspection so I use Range Technology so it diables the AFM. I think DOD would drive me crazy because I want V8 power all the time!

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They made GMT900s without DOD, all you have to do is install a DOD Delete Kit and reflash your ECU to a factory non-DOD tune. Then it literally IS stock.

I agree with BMP 100000% I had the exact same issue about a month ago. On the advice of the Blackbear team, I pulled the throttle body, cleaned it and while at it installed a catch can. Then did a relearn and it fixed the problem.