1993 2.4 High Idle

I have a 93, 2.4 L. It starts fine, runs fine but it goes into high idle (1200-1400 rpm) randomly?? It usually idles at 800 rpm. It might be at 800rpm at one stop light and 1200-1400rpm at the next stop light then is back at 800 rpm at the next stop light. I've also seen the idle jump up while I'm at a stop...

Any Ideas???

All comment welcome...

Thanks...