Very Low Idle on Corona

[.:O4AGTZ:.]

Well its a 91 Corona 4sfe automatic...the partners daily

Recently it has been idling quite low (350-450rpm). Most notiicably is when you shift it into Drive or Reverse and it goes the lowest. It has stalled once or twice.

Been serviced recently but was doing it since then anyway. Have not bothered to look into it until now as apart from that it is running as good as ever.

Any ideas what it could be? I understand that it could be a vacuum leak somewhere but is there any logical place to look or way to find it if it is?

Cheers

[.:O4AGTZ:.]

just had a thought...i dont think injectors have had any attention. If i run some injector cleaner through would that be one cause? I presume dirty injectors can lead to a low/rough idle