My hyundai Accent 2012 is having issues when accelerating.
It works great on low speed, but past 30kmh, if I accelerate more than regular cruising, the RPM will drop heavily and I can feel an heavy power loss, this lasts around a second, and then the RPM goes back to normal and the car keeps runningnormally. It will not happen at every "gear shift" (the car has an automatic transmission), but seems to be happening at the same time of trying to shift up.
I replaced the ignition coils, but nothing changed. I replaced the crank shaft position sensor. I replaced the spark plugs.
There's no check engine light at the moment. But there was one at one point that said "Misfire cylinder 4" and Random.
That's why I replaced the ignition coils and plugs.
What I have noticed (maybe it has nothing to do with my issue at all), but the spark plug well for cylinder 4 is super clean compared to the other 3.
The other 3 have some dirt in it (nothing intense), but the fourth one really struck me how clean it was. Anyways, I thought I would share this since it's part of what I have noticed when inspecting the car.
The issue happened after I went to the mechanic garage, they cleaned the throttle body part, and changed the oil. But that's it. Anything related to these things that might affect the car?
Thank you very much.