Rough Idle

I apollogise for not following the protocal for facilitating quick response, but I really need your help. An amature is I who bought this car (Toyota Corolla FX, Model AE101 1992, engine 1587cc, milage 110450km) three months back without profesional advice and check up by a knowledagble person in automobiles. The car's idle can go as high as1750 rpm. Also, it is a manual transmission and when I shift gears, the engine rpm remains high instead of going lower during the shift. It has been cunsumed alot of coins from me to my disappointment. Repalced are: fuel pump and filter, air filter, plugs. I've read about similar problems and most recomendations for remedy are centered around MAF sensor/AIS, oxygen sensor. I have then asked my mechanics about these gadgets and they seem to be hearing this for the first time in their lives. Being a car of decade and half, do these MAF sensor, AIS, oxygen sensor exist in my car. If yes. Where are they located? If no, what can really cure this annoying problem? I promise to be supportive to this great services you are offering. Poor John In Kampala Uganda.