I was wondering if other S2000 owners have noticed a drop in their RPM when idling. This morning, right after warming up my S2000, my RPM dropped to about 200-300 RPM. I thought I was going to stall since the engine seemed to just "die." I was in 1st gear but my clutch was depressed all the way. After driving some distance, it was ok, and idling normally at 800-900 RPM. This has happened in the afternoons as well, again after i warm the engine. Weird.

 

I've had that happen a few times as well, but it seems to go away after I start driving. Some have said it may be the Map senser. It hasn't bothered me enough to go back to the dealer.
But I'm pretty sure it ain't normal.

 

I don't have any experience with it... because I was just in the oppsite way as you did.. (my car's rpm raise like 3~400 rpm more ..) However, I still think there may be 2 ways to handle the problem... first, unplug your map sensor... then put it back again... or, change to the Denso spark plug..(IK22)... Denso plugs actually helped me with the problem for the increase rpm!! Those 2 ways won't hurt your car ..... yup, Denso plugs are expensive... but, it is a thing I think is a MUST for the car...!! so... what don't you try that... to see if same thing happen again!!

 

I have had this happen as well. A few quick blips of the throttle cleared it up. If someone takes this up with a dealer, please let us know what the outcome is.

 

It is most common with aftermarket air cleaners. Don't know why but a few blips of the throttle clears it up.

 

Interesting, because I put in a K&N

 

I just thought it was unusual since its never happened to my other cars. And yes, after driving a bit, it doesn't drop again.

 

I'm sure it's not the map sensor. Try having your IAT sensor replaced. Furthermore, I noticed this problem occurs more often on hot days.

 

I have a completely stock S2k and this happened to me the other day. I was kinda freaked out that it would just begin to stall while idling.

 

I notice that this happens to me just after the temperature goes to 3 bars and I have to stop quickly. With the temps being in the mid to upper 90's the problem has gone away.