Fizzboy7

For a few weeks now, I've noticed a "stumbling" or "jerk" from the transmission when coming to a stop. Like the car jerks forward slightly as the engine is winding down on the rpm's. It only happens when the car has been sitting all night and is cold. And only from about 3-2 mph right before coming to a stop. I've even noticed it once when accelerating from a stop (1 to 2 mph). Lifted foot of brake and it jerked slightly. (Maybe it's not even the trans?)
Is this a known problem? Can't say that I've heard of such a thing or seen anything come up in the search.
Thanks

moses0324

^^^I dont think their is a problem with the vehicle. I have experienced this in my Audi A4 and now my brand new Lexus is250. I honestly think it has to do with the ecu and or tiptronic transmission.

I think the ecu is the primary cause. It is trying to anticipate what you are doing. It doesnt know if you want to be in 1st gear or 2nd gear. It also might be due to the fact it is a tiptronic transmission. I have driven many cars without tiptronic but with an ecu learning system and it doesnt have this problem.

I know exactly what you are talking about though...Its especially annoying in stop and go traffic. It is very jerky. Im interested in seeing a solution too...if one exists

Bichon

For heavy stop-and-go traffic, put the transmission in snow mode. It gets rid of all that hunting and shifting; much easier to drive the car smoothly.

Little E

iTrader: (2)

Yup it happens. Check out my thread from a few months back:

shaking at the stop light

Emarati_K

100% normal

Fizzboy7

Thanks, that explains it all. Reading those posts, it seems to be the exact same thing. I'll still bring it up to the technition, just to make sure.
I am kind of surprised such a characteristic fell through the cracks in programming the car. Otherwise, the engine idle is so smooth you can hardly tell the motor is running.

VikH

iTrader: (5)

I believe you're talking about when it is below 37 outside and when the engine is cold. The car will rev and hold the engine at 1k RPM to warm the engine up quicker. This causes a jerky ride because at 1k the car is moving at ~10 mph. Like Bichon said, put the car in Snow Mode. This will reduce the jerkiness.

2slow

iTrader: (5)

It only happens to me when the engine is cold. I warm it up for 5-10 minutes before driving, but it still jerks forward when i start breaking toward a stop. It goes away after driving though.

Brian231

This often happens with my mother's 2003 Hyandai Santa Fe AWD. I even changed the tranny fluid with type "H" and added Slick 50 high mileage treatment. Although it shifts smooth, I still experience that same phenomenon. Definitely an ECU for the trans control.

omarban

I have this problem too in my 250, but it only occurs when I put the sequential mode in the 1st gear when the engine is cold and when I release the brake. This stumbling soesn't occur in "D" gear position and the same conditions. The stumbling disapears after 2 or 3 minutes. Is this a real problem?

ELL Y

iTrader: (1)

Lol. I suppose i'm one of those who doesn't really notice little squeaks, ratles, and apparently transmission stumbling. I've always assumed it's just a part of life :P

blake0387

iTrader: (1)

That's because even though your engine may be warmed up the transmission has still yet to move.

Byprodrive

iTrader: (1)

+ 1 my IS350 does this even when warm with 6 gears to choose from it gets lost some times. I should have selected the AMG option, MBZs have all fiberoptic wiring to speed info transmission & reduce weight.

Fizzboy7

This is EXACTLY how mine is too. Only when in manual mode, when cold, and only right when the car is about to stop or start moving again. It did it again this morning and this time I played with it. Crept foward by lifting off the brake and it shoots forward. Slow again to a stop and it jerks to a stop. Repeat a few times. Then once warmed up, all gone. I don't think this is right. Going to take it in.