G'day from Australia,  my name is Jason I have a 2016 Kia Sportage which is done approx 130000kms , start of this year my car was starting to jerk when I was at the traffic lights.  I returned to the dealership and they said it was a faulty spark plugs and got fixed and a few months later the same problem came back plus when I was accelerating it was jerking and the ignition light came on and so I immediately took back to the dealer last week. The mechanic now replaced the ignition coils and got the car back repaired. Its been 3 days with no issues until yesterday same problem when at the traffic lights slight jerks and watching the tachometer needle tipping down. I went to the petrol station and before I filled up I added a Nulon octane booster fuel additive and later filled up 60 litres of petrol and for some reason the knocking or jerking stopped. I feel this will be temporary fix. It's not a great experience. What could be when the spark plugs and ignition coils are being replaced??kind regards 

Jason . Love the show from down under. Keep safe