Recently bought civic 2018 90k millage. When stopping immediately, RPM drops to 600 and comes back up. And while in low speed, I feel a jerk when picking up or if I leave the pedal. Issue started a week after all fluids change and tuning from honda 2S. I took it back to them they cleaned the throttle again did re-learning but issue is still there. They did check the vacuum leaks etc but they say everything is fine.
What could be the issue?
- Fuel quality
- Throttle body or tps sensor?
- Plugs?
- Or maybe fuel pump?