Seems like it's more of a decel pop option than anything. From what NC-V and Higgs Boson have suggested, it just requires a little spark timing adjustment to smooth it out.

I do think it sounds cool for a stock config. I just got myself thinking after Jannetty's tests show the intake running lean. The misfire situation is especially suspect. I need to run my OBDII module and see if the ECM is detecting anything funky going on.

Haha. To be fair. Historically speaking... It's a fairly agressive cam! :biggrin:

Yeah i think its completely normal. Mine did that from the start, Especially when it was cold. I soon got a muffler delete and it did it a bit more. Bought a SCT tuner and it calmed it down a bit. Recently upgraded to CAI, Headers, full exhaust and performance tune, and it hasn't been until now that it went away.

My 2012 does it also.

From my understanding, all LS3 cars do it and L99 cars do not.

It has to be because of the camshaft. It's not "aggressive" but for a stock cam, i guess it is? lol

i have l99 and it does it

^^ here too ^^

Looks normal to me

My 2010 now has 23000km with cat back and k&n and has done it since i bought it with 5000km

My ls3 has done it since the day i got it, i had a buddy who is a tech look it up on some database and he found a document that GM posted saying that the LS3 and L99s have a bit of a "idle loap"

The GM testing procedure says to compare the problem vehicle side by side to a new one on the lot and if it is worse than the new vehicle to "repair accordingly"

I actually just took mine in because i wanted to be sure all was good before i do my cam.

Other than the poor attitude of the service manager all was good to go. :emoticon8:

so i guess the best answer is the most common one i have been gettin...

"they just do that" :yield:

is that dip caused by an accessory kicking on? like the fan, it has both low and high speeds. if you watch the RPM's when the AC comes on it'll do the same thing. and if you are hearing a squeak when it dips...then it sounds mechanical. but for the RPM's to hunt a little at idle, mine did the same thing.

My wife and I have the L99 in our his and hers '12s. Mine does that; hers does not.

I struggle to believe it's the "aggressive cam". Mine feels like miss, not at all like a lopey cam... My '66 Chevelle with the big block has the cam and lopes, this does not feel or behave the same. By the way, love tuning and working on the 66, no computer required...

What's the issue with the torque management piece mentioned above and how can that contribute to the issue?

If anyone wants to get their vehicle in to a GM dealer for an official diagnosis, please let me know. I'd like to help monitor what issues you're experiencing and document the case in our system.

All the best,

William R.
Chevrolet Customer Care

I have a 2013 L99 and mine's done it since I bought it. I brought it in to my dealer and had it checked, just to make sure nothing was about to fail on it. It checked out fine, according to whatever checks they did on the car.

its gotta be an aggressive tune/cam, nothing wrong with the car.