get a 3k carby, pull it down to every last nut and bolt, soak it overnight in a container of carby cleaner ( i just sprayed each parts with the can while holding it over a container.
I then rebuilt it to exact specs it says in the Toyota K motor manual. ran so perfect after that. no hesitation on take off, better responce, and way better fuel economy. did a 350-400 kay trip on about 40 litres. and thats a stock 4k, 4 speed, sat on 100 on the hwy, did a bit of town driving too, and i had me, missus, bub, pram, and other junk in car.