Toyota Repair: Engine jerking/missing @ 80-90 km

Question
Hi
I have a 2005 Toyota Caldina zt that stutters and jolts occasionally when travelling up hills. I have had the spark plugs changed and that seemed to help the issue but its still continuing just not as severe.
Was wondering if it could be the injector or are there any other issues that you have heard about?
Thanks heaps

Answer
Hello, I'm not sure if this engine has a distributor and wires to each spark plug or if it has one coil for each cylinder, in the first case replace the distributor cap and rotor and the plug wires, if it's the second case find out which cylinder is misfiring and replace that coil.