Hello,

I have a 2006 Hyundai Accent with over 102,000 km (63,000 miles). I am religious with my factory maintenance schedule.

Anyway I am experiencing two weird symptoms.

1) In the morning when I start my car, with my car on a slight incline, my car will rev 50 rpm up and down every 3/4 second or so as I am reversing out of my driveway. I have to keep my foot on the brake so it doesn't accelerate too much. When I get on the street, put it into drive and go, the symptom is gone.


2) When I hit between 65-75 kph while accelerating, my car vibrates a bit. It seems to be only when I am accelerating. If I, say accelerate to 80 kph and then left off the gas and left it coast down between 65 and 75 kph, I don't feel the vibration. If I am above 75 kph, I don't feel a vibration, and below 65 I don't.

Anyone have any ideas?

Thanks!

on the first one.....how long do you let your car warm up and do you have your A/C on?
on the second one, how are the roads where you live? you may need some alignment.

I don't usually let my car warm up in any weather conditions (from Ontario, Canada). Also I often have the defrost on because I like the indirect airflow. Perhaps I will try for a while with the air on another setting other than defrost.

I probably need an alignment, but what threw me was the fact that only when I stepped on the gas does my car vibrate a bit between that speed range. If I coasted down through that speed, it does not.

I think he's asking if your actual A/C is on, not just the air. If it is, try having it off when you start. Just changing the air settings isn't going to make any difference.

Is 75kph when the car shifts? I don't know what the shift points are in kilometers. That might be significant, although its most likely your tires or alignment.

#1 is likely normal, the engine idle will be different at cold than it will be when warm. Sometimes mine will surge similar to that and others it will just idle at a faster speed. Once the engine warms up the idle is fine. I figure it's either for emissions reasons or just to get the car up to temp faster.

I haven't heard any comments about the surging here other than yours but most have 2007+ models which likely have some different programming. Maybe theirs does not do it.

If you have an automatic, #2 could be some torque converter shudder. It locks up right around the 65 km/h mark (~40 MPH.) Occasionally if I hold the throttle just right (usually when I'm applying very little throttle) I notice a bit of a shake around that speed. Not something I feel entirely comfortable that the car does, but it's always done that and hasn't become any worse so I ignore it.

This post has been edited by hoosieraccent: Oct 4 2008, 11:56 PM

when I start mine from cold it will after about 40 seconds rev up a small bit then down, then up then down to normal... almost like someone tapping the gas in a old carburated car to get the choke/idle down..
i think it's completly normal. :)

On the second symptom...have you hit a curb or anything recently? I'm not talking about rubbing one with the tire, I mean like jumped the curb bent a rim type of thing. My car was doing something similar to that when I bought it. I would accelerate out of second gear (manual) and the shaking would stop. Mine ended up being a bent right axle. Don't know if yours is the same but it sounds familiar. You could just have a tire balance issue...but that wouldn't stop at higher speeds only get more noticeable. *shrug*

I guess I will start with a wheel balance, then get an alignment.

Issue 1 could also be caused by a bad TPS (throttle position sensor). With over 100k miles, it wouldn't surprise me one bit.

First, check to make sure your tires are all properly inflated and worn evenly before you spend any money.