Kind of sounds like you might have an issue with a lean or rich fuel mixture. Where the fuel hose connects to the fuel mixer [carb] there should be an adjusting valve that could have a small hex head about 8mm to adjust your fuel mixture. Toyota's had different types of valves. Could have a larger hex head type bolt with a jam nut or it might have a round valve with 2 flat sides for an open end 11mm wrench. You sometimes have to look underneath the housing because sometimes it's hidden. When you find it, start the engine and press the gas pedal to the floor and adjust it either direction until it smoothens out and runs good. Good Luck