Good day, i hope someone can give me some advice. I have a i20 (2011) 1.4 . Car lose power when i start driving , jerking and takes off slowly. (Only when engine is warm). Change plugs every month and it will be ok. Had a diagnostic test done and he told me its camshaft sensor. I then was told its oil valve on camshaft. He cleared it, i had it replaced and car is still doing the same, just a bit less. Any advice please?