My 91' Accord accelerates up and down by itself. This goes on for a while. Anyone have an answer?

 

if at cold idle, check idle control valve, if hot check egr

 

there are two different iac valves usualy both controlled by the temp of the anti freeze when looking at the motor u should see the two parts are atached to the throttle body (facing motor) the one on the right is the cold one the right is the hot one both can be cleaned but only the cold one can be taken apart and ajusted(careful be sure to research before just ripping into it) i'm not an expert but very thuro when i put my mind to it. any comments to this are more then welcome this is just what i have learned semi professional still an apprentice tho.