1986 Toyota Corolla rough idle

Hi, I have got a question regarding a 1986 Toyota Corolla. The car was given to me after it sat for 2 years in a driveway without being moved. Aftera battery swap it started up right away, but I didn't drive it anywhere since it wasn't registered. I changed all belts including timing belt, headgasket, replaced the vacuum lines on the carburetor, cleaned and checked the EGR valve, changed all fluids, spark pluges and wires, distributor cap, rotor, and most fuel lines but not the fuel filter. Oh I also replaced a leaking intake/exhaust manifold and PCV valve. I drove it in between repairs and initially the car would die at idle right away and only stepping on the acclerator would prevent this from happening. Now the car starts, but still idles very rough and I think the reason is the engine being flooded by the carb; the spark plugs are already plastered with carbon deposits. Most of the time the car only starts when I floor the pedal. Every once in a while, however, the car decides to operate absolutely smooth without any roughness or stalling at low revs. It seems that hard acceleration and especially kickdowns worsen engine performance again. Is something sticking in the carb? Shopuld I just drive the car for a few hundred miles in the hope that whatever is gummed up starts working again or should I take the carb out and rebuild it? Sorry this is a rather lengthy message, but I'm running out of ideas what could be wrong and especially why the car is so moody sometimes showing off its best manners just to return to bad behavior a few miles later.