Acceleration hesitation

06AtlantaLS

06AtlantaLS

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When I'm coming out of a turn or speeding up after braking the car often feels like it should be down shifting to accelerate much sooner than it does. There is a noticeable lag. I find myself giving it much more gas than I normaly would on another car just to get it to go.

Has anyone else noticed this? Does this make any sense? I tried to explain it the best I can...it's just kinda wierd.

It's a 2006 LS (V8 of course) with 23K, any ideas?
 
I've read that flashing the PCM at the dealer might help things like this. It's under warranty. Would they do this if I explained the problem and would it be covered?
 
I know these things are notorious for coil failure but i just don't see how it's possible on one this new w/ only 23k. I only drive the car 1-2 days per week and even then it's only to run a few errands.
 
I know these things are notorious for coil failure but i just don't see how it's possible on one this new w/ only 23k. I only drive the car 1-2 days per week and even then it's only to run a few errands.
 
Stupid Drive By Wire!!! :Bang
I am used to this because I have a Diesel (lots of turbo lag & Drive By Wire too). You just have to hit the gas earlier or put it in SST & select the gear it should be in.

I just got my car back from having the tranny reprogrammed by the dealer. It shifts a hell of a lot quicker. When I was accelerating really slow, 1 second would pass while shift gears. Now it does that in about 1/4 second. I will have to see if there is any improvement with the downshift lag problem.
 
Or get an SCT Xcal2 and a Torrie tune. It will eliminate 95% of the lag. I can't wait until I get my updated PRP so I can get my tune back in mine.
 
I have the same issue intermittently. It seems to be a combination of drive by wire and a slow reacting transmission controller.

Here's how it happens to me: You're cruising along at a decent speed in 5th gear. You slow down to about 20 because you're turning, or the car in front of is turning, whatever. You press down on the pedal to speed back up, you don't feel the car accelerating so you keep pressing a little harder. Eventually, the trans thunks into gear and you take off a lot faster than you had planned.

It seems tied to the adaptive function of the transmission controller. If you wind it up every now and then, the trans shifts firmer and downshifts quicker and the delay doesn't happen. If haven't pushed it at all for a few days, it goes into a softer shifting mode, downshifts don't happen as fast, and you get the hesitation.
 
MDavis0424 said:
I have the same issue intermittently. It seems to be a combination of drive by wire and a slow reacting transmission controller.

Here's how it happens to me: You're cruising along at a decent speed in 5th gear. You slow down to about 20 because you're turning, or the car in front of is turning, whatever. You press down on the pedal to speed back up, you don't feel the car accelerating so you keep pressing a little harder. Eventually, the trans thunks into gear and you take off a lot faster than you had planned.

It seems tied to the adaptive function of the transmission controller. If you wind it up every now and then, the trans shifts firmer and downshifts quicker and the delay doesn't happen. If haven't pushed it at all for a few days, it goes into a softer shifting mode, downshifts don't happen as fast, and you get the hesitation.
Click to expand...

Mine does the same damn thing. Irritating is an understatement. Figures I drive my car like it should be and don't beat on it and the trans acts up anyways lol
 
I also think the tranny itself is to blame. Since it is a 3 speed with overdrive used twice to achieve 5 "speeds" there are times when a shift and an overdrive has to happen at the same time. The 2-3 shift is one of those.
 
I'm surprised no one asked if he's checked the tranny oil. I remember on my 97 1/2 ton Chebby, if I went around a corner too fast (well, as fast as that poor suspension would allow, anyways), the tranny fluid would obviously shift to one side, and the pump would lose prime for a few seconds until the fluid stabilized and started picking up more fluid to send to the TC. This was with less than 1/2 of a quart under FULL.
 
On my '03 your not going to check the transmission fluid. There is no dipstick or not one I can find anyway. :)
 
Transmission fluid level can only be checked from underneath, you pop the plug out and if it drips you have enough fluid. I just had mine in for the 25,000 service so they were supposed to check the fluid level, . There was some kind of customer service bulletin on the early 2004 cars due to an improper transmission formulation, owners were supposed to bring the car in and they put in a special additive. There was nothing on my Oasis report about this having been done, and the dealer didn't know anything about it. Anyone have any information about this?
 
This happens to me all the time! And I have the Xcal2. Torrie gave me a tune that worked for a little while, then it stopped. So I flashed it back to stock, then put in another tune that shifts smoother. But still lags when I give it gas...
 
fuzzyb said:
I just got my car back from having the tranny reprogrammed by the dealer. It shifts a hell of a lot quicker. When I was accelerating really slow, 1 second would pass while shift gears. Now it does that in about 1/4 second. I will have to see if there is any improvement with the downshift lag problem.
Click to expand...

Lag problem
It's about 50% better. I wish it wasn't there at all but a 50% improvement - free, thanks to warranty.
If your under warranty and experiencing this problem take it to the dealer and get a "Program PCM to latest Calibration."
 
06AtlantaLS said:
When I'm coming out of a turn or speeding up after braking the car often feels like it should be down shifting to accelerate much sooner than it does. There is a noticeable lag. I find myself giving it much more gas than I normaly would on another car just to get it to go.

Has anyone else noticed this? Does this make any sense? I tried to explain it the best I can...it's just kinda wierd.

It's a 2006 LS (V8 of course) with 23K, any ideas?
Click to expand...

My first thought was that the AdvancTrac system was kicking in. If you're driving the car and it loses traction, AdvancTrac will activate and reduce throttle (among other things). This could explain the behavior you're observing.

Have you mentioned this to the dealer?
 
No, I havent mentioned it to the dealer yet but I'm going to. The other threads also descriobe the same problem I'm having. I don't think it's an issue of traction, it does this under optimal driving conditions, slow speeds, etc.
 
I had the same problm with my 2000 V8. The issue is clogged injectors, buy a good (Chevron) injector fuel additive. The problem will go away. No need to replace plugs and coils, total waste of $. The additive costs $10.00.
 
Does anyone have a list of the different calibrations done over the years? Or what's the date on the latest one available? just curious
 
This seems to be a common trait of the LS Auto tranny. For ALL LS's to some degree. I believe it has to do with the hydraulics and how they are used, or at least that's what I recall being told years ago by one of the 55RN Engineers.

Now that I have a second car to drive (1999 auto M3), the LS tranny drives me even more nuts. The M3 auto tranny has 3 modes. "Economy" or normal, Sport(it holds the RPMS longer before it shifts, and also stays in gear longer when you slow down..keeping the RPM's up in case you are just temporarily slowing for say..a curve, then are about to nail it as you are coming out of the curve..works flawlessly) and "Manual". Where it will stay in whatever gear its in until YOU decide to manually move the lever.

Even in economy mode, this transmission shifts quickly, instantly, crisply. There is NEVER a weird pause as you slow from say..30-18, then need to instantly floor it. There is NEVER a pause in manual mode when you are going through the gears and you KNOW you've hit the gearshift lever twice to move two gears..but yet it takes about 5 seconds to actually engage into that second gear movement you selected.

In short, the LS AUto tranny seems to be pretty sturdy and reliable, but sucks BIG TIME performance wise in a "Sport Sedan".
 
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