I have a 2007 Sonata, Automatic, 4 cylinder, 2.4 L, about 145,000.
Just recently I am getting an intermittent hesitation. Driving along around 50-60 MPH or so, steady speed, sometimes with cruise control locked in, sometimes not, it will start hesitating/bucking/surging/bogging/hiccuping (don’t know what to officially call it) a little. No check engine light, nothing weird on any gauges or tach, not throwing any codes. Speed even holds. If I hit the gas or let off the gas, it is fine. No problems accelerating or putting it into gear. Seems to do it when the engine is cold, and I haven’t noticed it once after the car has run for a while.
Took it to two shops including dealer and both either didn’t couldn’t replicate the issue, but one suggested/completed a transmission flush and new fluid but it didn’t solve the issue.
Any suggestions on what to check next or anybody have any first hand experience like this?