Weird problem occurred today, need some help/advice before I go take it to the local Honda dealer/repair. I'm not a car person whatsoever but I'm aware of these problems. This is a 2000 V6 Accord with ~208k+ miles, oil/fluid changed last month.

Background problems I'm aware of:
-May* have a coolant leak
-Previous odd idling problems but no where as severe now
-Issue likely related to "vapor lock"? IACV valve issues?

The current issue now is on startup my car automatically revs past 1.5-2 RPMs and goes down only to rev back up. It's nonstop revving every 2 seconds in every gear. Park, Neutral, Reverse, and Drive. I'm fighting it when it's in reverse or drive because it's always giving a little power even when on the break.

No idea what happened, it happened randomly on startup today after being driven around for a bit and now the problem persists. It's definitely not safe to drive and need attention ASAP. Just want some feedback before I call the Honda service repair shop in the morning.

 

I have had this to my old Prelude when the cooling system was low. I have also had it happen when there was a vacuum leak, but that only happened during idle. Another time I have had this issue was when my Idle Air Control Valve was loose and dirty.

I have a feeling the cooling system issue is the culprit, but check all 3. Regardless, that cooling system issue needs to be fixed. Make sure it is bled nicely, too.