My Accord has always had this issue when the fans come on, but it seems to be getting worse. If I'm at a stoplight waiting and the fans come on the car stumbles to about 500 rpm sometimes lower. What could be the cause of this? Any help would be great. Thanks.

 

every honda I have ever been in does this and as they get older, it seems like it gets worse...mine does that identical thing and sometimes I swear its gonna stall but never has....my 88 civic did the same thing also.

 

I would try cleaning out the throttle body, also remove the adjuster screw and clean the port and the screw, use carb cleaner to clean everything up , then set idle at 750 rpm