Costas

Yesterday I was exiting the parking lot of a gas station, and I had it in first gear because I was getting ready to get on the highway, and I was at around 3k rpm, then I pressed the gas a little harder and I was at 4k and my car started jerking like crazy. It felt like it was about to stall, but I was at high rpm's. This has happened to me before 2 or 3 times, one time in bumper to bumper traffic, and several times while going up a parking garage one night.

mikegarrison

Pilot-induced oscilation, perhaps? I don't know for sure if this is your problem, but it's a possibility.

When you are in first gear, sometimes you can get into the following cycle:

1) foot taps throttle

2) car surges forward

3) foot comes off throttle because car surged forward

4) car slows down, because foot is off throttle

5) foot comes forward because car slows down --> 2)

You can't feel your foot going on and off the throttle, but that's what's happening.

gosixers215

I think mikegarrison is right. I've had this happen to me a couple times in similar situations like the ones you described, and simply attributed it to my own fault. I'm pretty sure it's nothing mechanical, even though the first gear on my 2001 S can be a little finicky at times. I just make sure I ease it into first gear as much as the situation allows and make sure that the gear is engaged before I let 'er rip. If you get that bucking, I think the best thing is to let off the gas and engae the clutch until order is restored (correct me if I'm wrong anyone) Hope this helps even a little...

Costas

Aright thanks. I was worrying and thinking it was the car. I can't tell at all that I'm pressing the gas and letting go, but I guess that's what could be happening. I do know that whenever that happens I just press in the clutch again and start over and the car moves just fine.

mikegarrison

Yup. That would be it, then. It only happens in first because the throttle response is so sensitive in first, due to the gearing.

xviper

It may this phenomenon called "bucking":
http://forums.s2ki.com/forums/index.php?showtopic=57405

mikegarrison

That thread is full of very amusing theories, all of which are besides the point until the very last guy chimes in. The actual oscilation has nothing particularly to do with the airbox or the throttle or the electronics or any of that. It's an interaction between the response of the foot to the movement of the car and the response of the car to the movement of the foot.

But that makes it "driver error", so people don't want to suspect it.

JohnE

Try this "fun" experiment. Grab and continue to hold the seat adjuster (so the seat can move back and forth on its track freely). Now press the brake pedal and try to stop the car smoothly. Make sure you do this in an empty parking lot. It should osciallate nicely.

Intrepid175

Been there, done that, more often than I care to admit!

First gear throttle operations, especially in heavy traffic, takes more than a little finesse. Next time you get into this, just let off the gas and grab the clutch. When the car settles down, "gently" ease out on the clutch and try again. Don't feel bad about it. It's something that will catch almost everyone, sooner or later.

Drive Safe,
Steve R.

osc

Try being in the car when another driver is doing that ...its even funner!