My 2015 6.2 has terrible throttle lag, that combined with the A8 feels like it is surging driving in slow traffic. Multiple times at dealer saying"it's normal for new trucks".

Drove a 5.3 2018 Suburban this past week on vacation. No throttle lag and in LA stop and go traffic no feeling like surging hunting for gears like the 6.2/A8. They finally fixed that or the 5.3s not have it a pronounced?

 

Get a tune. Someone who dyno tunes would be best. These trucks come pretty held back from factory for gas mileage issues.
My buddy has a 16 and he got it tuned and pick 47 hp and 51 tq and trucks drives like it should.

Not everyone will get those kind of results, some trucks come tuned close to the best AFR and some came way off.

 

Wow, and you guys actually believe those results for just a tune?

You really believe GM creates individual tunes for each and every truck???

 

No I know since this cookie cutting design the have had for a long time there isn't different tunes, but I do believe on where the truck is makes a difference and that every engine even though it has a same build list and specs, each is difference enough to cause power level differences.
Maybe he has a weird *** truck I'm not sure.

My truck is an 01 with DBw and odd ball enough, with my mods in sig I make more power to the wheels than a lot of other with the same mods.

It was a dyno graph on each pull.

 

There is many things that can be done to manipulate a Dyno Graph to make a vehicle appear to make more power.

From what I understand on the New Direct injected engines, there isn't a whole lot you can squeeze out of them. They actually run very efficent. They may feel like a whole new truck but the real numbers don't lie.

Even Hpyertech with there generic handheld couldn't get more than 13 HP and 15Lb Tq out of there test truck with a Tune. And the only way they were able to claim that is by running low octane first, then High Octane and then tuning it on high octane.

I am sorry but its been well documented that a Tune Only Is not going to get the results stated above on these new direct injection engines.

The Old GMT 800 could get about 15 Hp from a tune only. These new Di motors average about 5-7 Hp from a tune. But the driving characteristics can be cleaned up so much with a tune. I have never seen any one get better 10 HP out of a tune only on these new trucks. Even the switch to E85 only nets about a 20 Hp change.

 

I don't think you'd get that much from just a tune. My LS1 '04 GTO maybe we got 10 hp but killing the TM helped it's driveablility and track times. Also I have heard that for warranty work they can tell on these newer computers if it has a tune in it or been changed before.

I do believe GM and OEMs for each engine combination have a specific separate tune. They spend hundreds of hours on dynos dialing them in for efficiency mainly and driveability. Good Pontiac racing friend worked for Ford on their boosted stuff-LOTS of dyno hours.

My main question was do the 5.3 have the same throttle lag from the factory as my 6.2. My brother in-laws '17 5.3 he has not felt it but his shudders going from V8-V4 mode. My 6.2 is smooth there.

 

The "lag" most people feel is really a limiter to how fast the computer allows the throttle to open. This is actually to make it easier and safer to drive since you dont risk loosing traction as easily, especially in austere conditions.

I tune professionally and I havent even messed with the tune on my 2018. It drives very well and after pulling the tune to look at it there isnt a whole lot to be had. The thing most tuners do is increase the driver demand table, which is essentially the same thing as pressing the pedal harder.

 

Most of the gains on the new GM’s come from tuning the trans tables, the engine tunes are actually pretty close. Tuning trans settings and adjusting pedal response help with the feel but don’t change final power.

 

When I go to change lanes and hit the gas and it takes a second to actually go there it can be dangerous. Worse is coming to a quick stop then trying to go. Falls on it's face like a bog. Then in stop and go freeway traffic you are doing lots of that on brakes on throttle -feels like it is surging. If it was one of my carbed hot rods you would think the carb needed a LOT of dialing in.

My wife's '02 Avalanche an my '04 GTO are still cable throttle bodies so not lag. Step on the gas and go. Which is what that '18 5.3 Suburban we rented did-no lag.

I think the throttle by wire and it's programming is not really dialed in on the 6.2. Lots of Camaro and Vette guys also have the same complaint. Service guys always say "they all drive like that now".

If you can not modulate traction issues either from acceleration or braking you should not be driving! Funny how for decades drivers had to do that.

 

An update for you all -still bad lag ,the worse time is when it has been driven only a few minutes and a quick stop and go. Almost feels like it brake torqued and launched.Since n the 2015 the Grade Braking On is the default possibly that and the brake releases slower than the truck wants to go. Let off the gas then back in again feels almost like motor reved a little against brakes. Still has the surge feel in stop and go driving.Does average about 21 mpg unless I am pulling car trailer. Stillhas the best brake pedal feel of any car, truck,race car I have ever driven!

just picked up a 2021 6.2 Z71 for my wife. Totally different driving for the better,even when it cuts the engine off at a stop there is hardly any lag,no feeling like surging as shifts gears-I realize a different transmission. Also you have to turn on the Grade Braking. Brakes have different fixed 4 piston calipers and the pedal is real sensitive and they are grabby.Reverse camera clarity is WAY better too.