yah yah.... the carb kit consist of what??... can DIY tune A/F ratio as well??... i heard that wide-band O2 sensor used to tune A/F ratio vr expensive....
For injection cars(Proton) you can check on the below thread :
http://zerotohundred.com/newforums/showthread.php?t=73347
I have posted the photos where's the problem start. You can send the car for cleaning the whole fuel injection system, but it will cost you 300-400, but my method only need a screw driver and a clean cloth.