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3 Mechanics in a row don't know what's wrong with my '04 Accent

Hey everybody, this is my first post on the forum.

I own an automatic transmission 2004 Hyundai Accent with about 180,000 miles. I bought it brand new, but it seems to be having trouble shifting into the right gear. Many transmission “specialists” keep telling me they can’t figure out what is wrong, aside from offering to completely rebuild my transmission. The car has the following symptoms:

1. At a stop sign or red light, my car doesn’t always begin idling properly. Sometimes it just won’t go anywhere at all, even with the motor running.
2. As I drive down the highway, it acts like it jumps into a higher gear for no reason. It sometimes resets itself with no action on my part.
3. The car jerks back and forth, not seemingly due to shifting into gear, but randomly.
4. The check engine light does not come on often, but by the time I can use a DTC reader, the light goes off.

Everything seems to be intermittent, so I can’t replicate the problem on-demand for anyone who wants to inspect the problems. Is there anything I can do? Is there an easy way to figure out what’s really going on? I’m assuming this is transmission-related, but I’m open to suggestions. Thanks for any help you can provide.
— Jay

First of all, have you done the regular transmission maintenance recommended in the user’s manual ( change trans fluid and filter at regular intervals)? When was the last time you had this service done?

Even if the check engine light goes out there may be some stored codes. Have you checked?

"my car doesn’t always begin idling properly. Sometimes it just won’t go anywhere at all, even with the motor running.

  • I can’t make heads or tails of that. Elaborate on the idling issue. Then elaborate on the “won’t go anywhere.” Describe.

“acts like it jumps into a higher gear” That also needs elaboration.

Many code readers/scanners will read history codes. You need to find a shop with the right kind of equipment and have the codes read.

A full run down of maintenance history, including transmission would be helpful.

Those times when you’re at a stop sign or red light and you press the gas but the car “won’t go anywhere at all”, does the engine fail to rev or does the engine rev but the car fail to move? Or are the symptoms entirely different?

If the engine fails to rev at all, than the problem is with the engine rather than the tranny, and that would be consistant with the other symptoms in your list. I believe that this car has an accelerator system that sends a signal from the pedal to the ECU and then to the throttle body, as opposed to an old fashioned cable. If I’m correct, I’d first (if downloading stored codes was nonproductive) want to get a helper and see if the throttle body is responding properly to the pedal. It might even be a good idea to remove and bench test the pedal assembly.

Cleaning the throttle body might help in this case as well. It may be gummed up with deposits and acting erratically mechanically.

Post back. We do care.

“The check engine light does not come on often, but by the time I can use a DTC reader, the light goes off.” Read the codes history, or when CEL is on, that is sure fire method 1, I have a wag it is a vacuum issue, check the vacuum lines.

The above comments are good. The OP should dod what required read any stored codes, that’s step 1. To me, this looks like a case where the OP should start saving up money for a transmission rebuild. I have a Ford truck with an auto-tranny, and when the tranny got to the point where it needed rebuilding, the symptoms were pretty much exactly as posted by the OP. It could be a computer problem, or maybe something just needs adjustment. Only the dealership or a transmssion shop can tell for sure.

Even when the check engine light goes out, the codes are stored and can be retrieved. An AutoZone or similar auto parts store will read the codes for you, post the actual codes to help get more ideas on your problem.

I can’t tell if this is a motor issue, or a transmission issue. Some of the comments seem to indicate the torque converter is not functioning properly and/or smoothly.

There’s really only one choice here. It’s obvious, so I won’t go into it.