Hi,

I bought a 08 uplander about 2 months ago, when it's stopped at a traffice light, then I remove foot from brake padel (but not step on accelerator pedal right away), I could feel a short shake or tremble while it kicks in. I was told by salesman that it could fade away after 3000km break in period, it's 4500km now but it's still there. I went to GM dealer last week, they did notice the shake/tremble but they told me it's a kind of "normal" on a big engine such 3.9L, there is nothing to do, unless GM could make a updated firmwareof vehicle computer balabala...........

I'm wondering if everyone's uplander has same issue like me, I have drivenabout 10different car/vans, include Chervolet Savana, I just never found same such shake/tremble on any of them.

 

My '07 does the same thing. I think it is a minor "trait" of the vehicle and we are quite pleased with the overall performance of the van.

 

My 07 does a rumble/chug thing at lights. Even with my foot on the brake it has a small lurch forward then all normal again. It happens infrequently and under varying conditions. And in warm weather it occasionally makes a noise that sounds like putting a pencil intofan. Bdbdbdbd then it goes away.

Quirks of a mediocre vehicle.

 

that quirk is prolly the electric fan kicking in so you mediore vehicle dont overheat and susplode.

 

I just got a brand new 09 as a work van and it does the exact same thing. Nothing to worry about. Its just the engine struggling slightly to move the van forward

 

update on this issue....

With just over 5000km on the van, the ECM seems to be compensating for this problem a bit. It only does it once and a while, and when it does, I hardly notice it.

 

The stumbling to me doesn't feel like an engine issue, it almost feels like the torque converter trying to lock-up momentarily while the vehicle is standing still. Again, it's a minor "quirk" that I can easily live with.

 

Torque converters are designed to not engage untill the engine is warm, shifter is in drive, foot is off of the brake, you have been cruising at a steady speed for a bit, and vehicle speed is above 50km\hr. So I highly doubt it is the torque converter

 

I believe a computer is causing the stumble, not compensating for it. A bug in the software. Just my $0.02 Canadian...

 

these little shakes are caused by the stabilitrack and it is perfectly normal. If you read your owner manual it will tell you about this problem. I have an 09 and sometimes I experience this if I releise the brake pedal a bit when stopped