somethins wrong and i cant figure it out!

i dunno what actually happened to cause this but for some reason now almost everytime i step on the gas, my carb or engine in general bogs or backfires
it runs ok at idle but still sounds choppy. it also runs ok in the low rpms but there is no difference in the take off whether im at 1/4 throttle or full. ive heard different things from a couple of people, but nothin to helpful so any guidance would be greatly appreciated! thanks