Is your engine a 1.0 litre 1KR-FE? This engine is notorious for have the EGR Valve clogged. Since being in Lahore, I have seen countless hundreds of mechanics, both private, and the Toyota dealership, say that "You should remove the Catalytic Converter." This is not solving the problem. In actuality, you are making the Engine WORSE off from removing the Catalytic Converter. This is a very SLIM chance that the Catalytic Converter would be clogged unless it was a very high mileage car and the air/fuel mixture was not problem set (Think MAP Sensor gone bad). The thing is, if it is a bad Catalytic Converter, then it should be replaced with a new one or a good second hand one. Look for the EGR Valve (Located behind the engine, under the intake manifold on the right side) and have it cleaned, along with the EGR passages and see if that sorts it out. You might need a new EGR gasket, and I have a few that I ordered from Japan, so if you need one, private message me.