5S-FE MK2 Non-Turbo Engine Need help! Engine bucking and jerking at certain RPMs

5S-FE MK2 Non-Turbo Engine, cold, gear, bucking, range, started, driving, symptoms, bucks, rpms, idle, rough, distributor, spark, replaced, happen, engine, parked, feel, feels, jerks, start, 1.5k, tree, leaves, pine, appreciated, bunch, weeks, work, 3k-3.5k, 1000, timing, time, needles, subtle, belt, sensors, rotor, body, throttle, plugs, wires, pump, plug, greatly, serviced, water, beginning, home

1991 MR2 N/A No mods. Problem: Car bucks and jerks at certain RPMs especially when cold. Symptoms: 1: When the car is cold, idle is rough at the 2k range. Before the car would start idling at 2k then slowly go down to around 1200 as it warms up but now it idles at 2k for around 3 seconds then goes immediately to 1.5k. If I rev it to 2k the engine feels a little rough, like its not getting full power. When the outside temperature is cold, the roughness is worse.