Hyundai Repair: Intermittant problem in Hyundai Accent, hyundai accent, false signals

Question
Hi,

I own a Hyundai Accent (2002, GT) with 75K Miles on it. Recently it has developed a problem. After I run the car for around 50 Miles, it starts getting false signals on the speed & then either it refuses to accelarate or maintains the speed even if I don't apply accelarator. It also changes the gear abruptly during this period.
The RPM indicator constantly is above 2-3 at that time. This problem sometimes comes in the morning also when I start the car first time.
The mechanic did the computer check, & there was nothing found abnormal.

Also to mention, I have recently changed the entire transmission.

Let me know if you have any clue on this.


Answer
I'm not sure what you mean by "false signals on the speed," but it definitely sounds like a transmission issue.  If you haven't taken the vehicle to the shop that originally diagnosed and replaced the transmission, then you should do so.  If they're the ones who cannot find anything wrong, I'd recommend contacting them and advising them that you'll be taking the car to the dealer for diagnosis and that if there's anything wrong related to their diagnosis and repair, you'll expect them to pay for any related diagnosis and repair you need to have done elsewhere.  If they don't want you to bring the car back to them, then take it to the dealer and find out what the dealer thinks is wrong and work from there.  Be sure to tell the dealer what work was done.