High idle problems on 84 SR5 corolla

hallo, Alright, My 1984 SR5 Toyota corolla. And my engine is now giving me some high idle problems, In gear, it will slowly come down off the RPMs, but in nuetral, It will rev to 3000RPMs, or 2000, or just under 2000. And even totaly warm, it will not drop. when I got it it did this, but If I tapped the gas, It would come down. Ive got the carburated 4ac motor, anyone have any ideas?