Do you know why my Accent is jerking?

I have an auto 2003 Hyundai Accent and it has 40,000 miles on it. This summer I noticed it started "jerking". It typically happens when I could get into my car after work, start it up and put it into reverse or drive. It could jerk forward quickly, then do it again some more times while I am driving till it goes away. It could then become sluggish in accelerating after stopping at a light. Now it jerks on the highway, but instead of going away, now it'll shift into this strange mode that sounds like a deep sound at about 60+ mph. It sounds good at 55.

I noticed it happens after my car was sitting in heat for a extended period of time and does not go away till I turn my car off, then on again. My check engine light doesn't go on.

I also brought it into the dealership to check it out, but since it does not "act up" for them since it is natural they can not fix it. I have been driving with this problem for about five six months.

An educated guess could be a problem with the EVAP system possibly the canister close valve not opening and pressure builds up in the fuel tank.Take it back to dealer and ask them to check the evaporative emmission system for faults

Ex Hyundai tech

rebel speak slower next time

It's hard to say what it may be. may be a bad transmission but it just may be a sensor. I am leaning toward a bad sensor but the engine light could come on for that.
Did you leave the car at the dealer ? Some will drive it around for a while but some will only go around the block then walk away. I am not sure if a dealer will let you ride with them while they are driving it but I know some good fix shops could let you.
It's a ache but take it back to the dealer and tell them to drive it for a while because there's a problem but it only happens as you portrayed.

I had the same problem with my 99 auto. I ended up selling the car, but before I did I was told that it may be a sensor, a problem with the overdrive, something to do with the transmission and it gets worse, because it did start to turn my check engine light on. When I got it checked out it said that one of the gears was stuck on . I clarified that the problem did not stay that it came and went so they turned off the light, but it happened on more than one occassion.

try lining up the front wheels, or get the transmission looked at.

Call HyundaiUSA buyer affairs. Tell them the trouble, tell them the dealer is kicking the problem back to you, and have them arrange for a loaner. They have to drive the car long enough for the trouble to happen.

Another approach is to have roadside help come tow the car back to the dealer because the trouble is too serious. No trouble found? Do it again. sooner or later, the factory Hyundai will lean on your dealer to fix the problem, because the towing bills start to pile up. If a check engine light is on while the car is stumbling, it should set a code in the computer. That may be read of course, but probably, your dealer clears it and declares no trouble found. it is hateful, but you must lean on them. Do it before 60,000 miles, Rosie, it sounds costly.

Best luck.