I have a 1997 Honda Accord EX with automatic tranny that has just taken to revving somewhere between 1 and 2.5 RPM's while in Park or Neutral on it's own. Recently, I noticed when I'd shut the engine off that it sounded as if the cooling fan turned off right away, then came back on, shut off and came back on, again...then shut off for the final time. I thought this pretty odd. The next time I went to start my car in the cold weather, it started normally, then suddenly began to rev between 1 & 2.5 RPM's on it's own. I shifted into Reverse and it stopped revving. When I shifted into any of the other "Drive" positions, it acted fine, but in Park and Neutral it started revving, again. After about 10 minutes, I noticed the temperature gauge was in the "danger" zone, too. Thought it might be the water pump, but can't find anything to support this theory. Please...can I get ideas???

 

I know the cooling system needing bled can make the RPMs jump up and down. With it overheating as well the first thing I would do is bleed the coolant with the bleed screw by the thermostat.

 

Thanks SO much...that's exactly the information I needed!