Why is my 2007 Opel Corsa Lite 1.4i jerking when I drive it? This is not happening every day

mine did the same. when I opened the cam box I found that my cam was damaged as well as my rockers, I fitted a new cam, new rockers and new lifters now it is 100%, the problem is that some of your oil ports on the lifters are blocked by old sludge oil, either just clean everything or start with replacing the lifters first, but once your cam box is open and u can see the cam u will know, if there are no damage to the cam or rockers then u lucky then just clean your lifters and the ports they are in. Clean thorroughly so there is no blockage so the oil can flow freely. Don't use the old lifters buy new ones, its +- R40 each depending on the spare shop they are R35 each at Cotwals buy all 8 mine did the same. when I opened the cam box I found that my cam was damaged as well as my rockers, I fitted a new cam, new rockers and new lifters now it is 100%, the problem is that some of your oil ports on the lifters are blocked by old sludge oil, either just clean everything or start with replacing the lifters first, but once your cam box is open and u can see the cam u will know, if there are no damage to the cam or rockers then u lucky then just clean your lifters and the ports they are in. Clean thorroughly so there is no blockage so the oil can flow freely. Don't use the old lifters buy new ones, its +- R40 each depending on the spare shop they are R35 each at Cotwals buy all 8