the problem started last week my wife said the car overheated. when I checked the coolant it was empty, filled radiator started it and the idle went from 2000 rpm down to 800 rpm and kept going up and down. after the car got hot the fans didnt come on. checked fuses all good.

NEED SOME HELP PLEASE

 

need year and trim level of car ... but we've seen this 100X over. It could be:

- FITV - Fast Idle Thermo Valve
- vacuum leak

 

1990 accord dx

 

vacuum leak or air pockets. You'll probably need to bleed your cooling system.