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So my old '97 is getting tired so I bought a 2015 1500 6.2 8 speed 3.23. It has what I would consider driveablity issues, heck even my wife noticed them. But being a carburetor tuner for 40 years I'm not sure if it is factory issue or not that can be tuned out.
Cold(and we're talking 70s first start in morning not real cold here yet) has some serious flat spots for 5 minutes-like a carb with the choke not adjusted(my Vortec 350 97 drives great cold).

Part throttle feels like a carb that is lean surging especially right when it shifts fall flat at first then pulls. Not sure if at part throttle it is hunting for which of 8 gears or the factory TM has it turned down so much the motor falls off during the shift. This is slightly better when Tow/Haul is on.

Factory tune issues or my truck itself have an issue?

Any one tuned on these yet or driven them?

Vortec350ss

iTrader: (20)

<p>I have not tuned or driven one. But I have heard some iffy reports about them as well unfortunately. And 70 is far from cold... Hmmm.&nbsp;</p>

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Just don;t know how much is the factory tune or some actual issue. And if the factory tune get someone to tweak it out

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New thing today -person tried to run into me in a parking lot hit the brakes , then gas to get out of the way-nothing happened for a second or so probably 25% throttle then it screamed up like a lag on the throttle. Thought I heard somewhere there is some lag on the "drive by wire" pedal in some of the new GM vehicles.

2xLS1

iTrader: (25)

It's a new truck. Take it back to the dealer and complain.

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I'll gladly take it back if it is a real problem and not the factory "tune". Then the dealer keeps it for 2 days-"It drives OK for us" so time to drop it pick it up and it still drives the same. BTDT to many times with intermittent issues. Wife's 2002 Avalanche spent lots fo time at the dealer for A/C system turning off automatic climate control blowing cold air in winter unless on max heat-"can't find a problem".

Heard from a few sources the throttle by wire has some lag time, and 8 speeds do some of this. Just seeing if anyone else here has seen the same from factory settings or a problem.

storm5.3

iTrader: (1)

Mine does the exact same thing !!! I thought it was just a cold engine...I'm down on the coast from you south of Bay City...first run of the day or after sitting awhile and yep I get the hesitation on accel like bad gas or a miss or something. Mines a 2015 6.2 8-speed Denali CCSB.

Also I have the infamous shake/vib at speed (over 70mph) dealer replaced 3 tires saying they were out of spec. Sill does it !!! Tires are Goodyear Eagle LS-2's...truck sits in the garage most of the time...almost too pissed to drive it !!!

Zed

1FastBrick

iTrader: (17)

If you guys don't report the issue, Gm wont try to fix it.

I am sure they will have a software update if they don't already have one.

Most new Platforms or Engine Trans combo changes have them. I think the NBS 99 Silverado had like 6 different calibrations for different issues with idle, stumbles, transmission shift issues.

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A mechanic buddy today is checking my VIN for any software upgrades for driveablity. He has an older 6.2 Denali 6 speed that did some of this that a tune helped a lot. A guy in Victoria is supposed to be the 6.2 guru. Throttle by wire lag is some of it, factory tune "tranny nanny" that TM kills timing and even kicks back throttle on his when shifts to save the tranny is a lot of it also on his which could sure be giving a surge feel when driving part throttle as shifting between 8 gears.

LSX Power Tuning

iTrader: (2)

I just tuned one that had vibration above 80mph, he wanted the speedlimter raised so I raised and once he got to about 95mph the drive shaft broke. Once he got it back from dealer with new driveshaft, exhaust, and few other parts there is no more vibration.