1994 Honda Accord Engine power drops when clutched down

I drive a 1994 Honda accord,recently its takes like two to three attempts to start my car in the morning and it seems to idle well when started,but when drivien into the highway i observe that my engine rpm suddenly drops below the 900-1000 stable value when ever i clutch down to move either to a lower or higher gear,this experience is worsened if i have the car A/C on while driving.Please what could be the likely cause?.