14 LTZ Shutter/shake/ vibration under light throttle

[TaboltB2015]

If the GM dealer did the work, take it back and explain the issues to them. A slight metal rattle could be something as minor as a loose heat shield that they bumped or did not reconnect after the TC repair. Vibration, could that be your AFM kicking in and off and its more pronounced now with the new TC? Random shake on the highway at 70-75 could just be tire balancing. A weight or two could have come off while they were doing some work, etc. as well.

Yes local GM dealer did the work I was recommended to them from co worker that has all his stuff done by them. Tires were put on about 9k ago, I’ve thought maybe it’s because they are 22” but would think if there was a issue I would feel it all the time not just on light acceleration, I will watch the dash on the V4 to V8 to see if that’s when I feel the vibration

 

[that331racer]

Just speculation, but you might have torque converter shudder.

 

[TaboltB2015]

I will try to get a video of it later when I get home from work

I got under it and was touching anything they would have taken off and the rear clamp on the exhaust was put on but was not tightened down.. first picture is before I tightened it 2nd is after lol simple clamp, feel like they would have doubled checked before they put it back down on the ground. I drove it and no noise

 

[TaboltB2015]

If the GM dealer did the work, take it back and explain the issues to them. A slight metal rattle could be something as minor as a loose heat shield that they bumped or did not reconnect after the TC repair. Vibration, could that be your AFM kicking in and off and its more pronounced now with the new TC? Random shake on the highway at 70-75 could just be tire balancing. A weight or two could have come off while they were doing some work, etc. as well.

I watched the dash from where it goes from V4 to V8, most definitely feel the vibration in V4 with holding light throttle it’ll stay in V4, anything more than that it’ll obviously go to V8 but the vibration stays can definitely feel it “kick” back into V8. What a goose chase

 

[j91z28d1]

might be a good idea to get the 4 cyl mode turned off as soon as you can. I doesn't keep it from eating lifters but as far as I've seen, it doesn't hurt and you'll need it turned off anyways when you go full delete

 

[jdwood1111]

I watched the dash from where it goes from V4 to V8, most definitely feel the vibration in V4 with holding light throttle it’ll stay in V4, anything more than that it’ll obviously go to V8 but the vibration stays can definitely feel it “kick” back into V8. What a goose chase

Yep, sounds like the afm system is what you are feeling. Couple options:

range device will plug in to your obd2 port and keep that from occuring but need to be taken out to pass inspections. It’s around $240 on Amazon.

There is a place/guy you can send your pcm to I believe that will turn it off for around $50 if I can find the link I’ll post it up.

Find a local person that can tune it out with HP Tuners or similar. My guy would turn it off for $200 but did a full tune for $600.

I went with the range device to start that worked and then had a custom tune done which included afm turn off.

Glad the metal noise is sorted out. But check that exhaust, is that a pin hole I see?

 

[TaboltB2015]

Yep, sounds like the afm system is what you are feeling. Couple options:

range device will plug in to your obd2 port and keep that from occuring but need to be taken out to pass inspections. It’s around $240 on Amazon.

There is a place/guy you can send your pcm to I believe that will turn it off for around $50 if I can find the link I’ll post it up.

Find a local person that can tune it out with HP Tuners or similar. My guy would turn it off for $200 but did a full tune for $600.

I went with the range device to start that worked and then had a custom tune done which included afm turn off.

Glad the metal noise is sorted out. But check that exhaust, is that a pin hole I see?

I started to look up just a simple plug in one, found the range one as well, luckily I don’t have inspections here in Kansas so don’t have that problem, I’d really would like to have it deleted all together but the shop that I see that does it and looks like they do great work is pricey at about 5k for a complete rebuild, tune, ect. On the exhaust I think that is just dirt built up, taking about that dark spot just after the cat?

 

[tuckerrnr1]

I will second or third on the Range plug in. My 2010 did exactly like you are describing and that cured it.