Hard starting, engine vibrate when start & check engine lights on.

1st, my check engine lights on then i send to proton technician for check /repair. But the problem still the same.
Now the engine very hard to start, i've chg. spark plug, timing belt, check wiring system,Diagnose setting & etc.. but still the same problem. No technician can solve this problem. Now they pointing on the engine saying it need to over haul.. but im not agree about it coz i know my engine has nothing with it.. pls. help