It seemed like my 2.7 fell flat on it's face this morning! Here's the story...

On way to work, have the traction control off (double tap - AdvancedTrac/Sport Mode), Sport Mode selected, on 2 lane, 35mph road, switched lanes to go around somebody that was turning, gave it about 1/2-3/4 throttle, and nothing! (Thought I was back in my old Tahoe for a second! )

I had my music up pretty loud, so I wasn't able to hear the engine, but right as it finally started taking off, I looked at the tach and it was racing up to 5-6K.

After what seemed like a 2-3 second lag, it finally took off right as the truck behind me was barreling towards me.

Don't know if the transmission was waiting for the turbos to spool first, or turbo lag, or possibly the trans was slipping...

It has done this before when trying to gun it, but not quite to this extent, and I think I had it Sport-Mode then also. Normally the throttle response is spot on, but this has me concerned.

Anybody else experience anything like this also?

 

The sport mode keeps the engine in higher rpms. Which is good for short little bursts of acceleration, but if you floor it, it'll almost go to redline before shifting down, so there's a delay there, especially if you're already cruising at high rpm's of 4500-5000+.

Sport mode is finicky because of the long hold. If you slow down a bit and let the engine upshift first, it should respond quicker. Personally I only use sport mode from a stop and find it more of a pain while driving.

 

My guess is you gave it enough throttle to overpower the traction available at the time (gas turbo torque), and your right rear tire spun until the traction control pulled back the power a bit to regain traction, then off you went. Maybe you were on a low traction surface at the time. Might have heard this going on if the music wasn't thumping.

Double pressing the AdvanceTrac button puts the system in Sport Mode which enables Stability Control and Traction Control with higher threshold targets. The higher threshold targets allow more sideways slip (before stability control activates), and more tire spinning (before traction control activates) than AdvanceTrac in normal mode.

In other words, Sport Mode allows you to have a bit more fun slipping and sliding the truck around on, say, snow or dirt, before the stability and traction nannies bring the truck back in line to maybe prevent a full spin.

A single AdvanceTrac button press leaves Stability Control enabled and disables Traction Control. Press and hold button for 5 seconds and both Stability and Traction Controls are disabled. Roll Stability Control is always on except for 4WD LOW.

Or, maybe your truck has a real problem, hard to know for sure. You could try to replicate the conditions and see what you feel and hear. Good luck.

 

Yeah I thought about the possibility that I may have been spinning a tire or 2, but I think I would have felt that, especially if just one tire. Otherwise, it would have been one hellava burnout.

And when it did it before, the traction control was not pressed, and I know there were no tires spinning then.

So if it like boost says, and there is a delay for some reason, then that makes me feel better that it may not be a trans slipping, but then makes me mad that it could do that again right at a bad time.

I'll play around with it some in both Sport Mode and reg mode and see if I can get a better feel for it.

Anybody else want to add to the experiment and post their results?

 

could be a combo of "redlining", tranny shifting and traction control kicking in all within 3-4 seconds...

5k rpms, you punch it, rpms fly up, one tire spins like crazy, tranny upshifts while TC cuts power, meanwhile you are back at lower rpms, and nothing happens? hopefully it's nothing more than all the nannies fighting each other for a short moment...

 

TerryH22:

I think its a combination of the ever-so-slight turbo lag and the time the transmission takes to downshift at that speed. Together, those make it seems like a long delay.

I know because I got stuck under yellow a couple of times in a nearby municipality that has red light cameras. It has happened a couple of times, both in sport mode and regular mode. I experimented with it on a side street, the delay around 35 mph seems the same (meaning: a little long) in either mode.

I'm writing it off as a characteristic of the vehicle. And no...I haven't received any tickets yet, although I think it was really close a couple of times.

 

I've experienced the same issue in both Reg and Sport modes..... I'm not a big fan of the behavior and hope it's a characteristic and not a problem.

 

It happened to a lesser extent to me again yesterday in reg mode too.
It only seems to happen when I switch lanes to go around somebody and gun it to get out of the way.

Maybe that's just when I notice it most since I'm looking in my rear view mirror and thinking I should be moving a lot faster!

But if I just want to zip around somebody, the throttle response is spot on, just seems to happen when you 3/4 throttle or so.

 

Good points...

 

I read something in another post about recalibrating the throttle position sensor by turning the key to on but not starting the truck and pressing the throttle to the floor slowly and letting off then turning the key off. I think it was like 3 times or so that you do this. Maybe if you try this it could help IDK?