Up until now the s2000 has been a great car for us, no problems, no nothing. The past couple of days, when I start up the engine it will idle to about 2k RPMs and slowly drop to about <1k RPMs once it is fully warmed up. I have noticed something strange has has begun to happen. Sometimes on the warm up the car will rev itself?! It will actually start revving on its own up to about 3k RPM. By no means it does it very much, maybe once or twice but it scared the heck out of me when it started doing it on its own. Recently I got my mom in the car and as luck would have it, it started revving itself when I was locking up the house for her, scared her too. I vaguly remember someone else mentioning this but I can't seem to find the post.

Weather wise, nothing out of the ordinary....50F not much colder than that and this thing has been on in 15F with no problem. No humidity in the air. Overall not really a problem, just wondering if it is something that I should be concerned about.


Regards,
Jonathan

 

Whack the Map sensor on the throttle body with a screwdriver handle.
Have you driven it agressively? It needs to get hot now and then.
If it continues to do it after driving hard then have them check your O2 sensor. I believe the ECU uses feed back from the O2 sensor to determine the idle speed.

 

Also, your Idle Air Control mechanism may be having some issues.

 

My '03 only has about 6k on it but it's always started idling high around 2k and dropped down. It's revved itself a few times too, I think always in the winter. It doesn't seem to be a problem for me.

 

Check for air leaks. A Vaccum line may be detached.

Speedracer.

 

[QUOTE]Originally posted by Sideways
Whack the Map sensor on the throttle body with a screwdriver handle.

 

There is a series of checks and tests that must be administered to check for a fluctuating idle speed. One of these involves the IAC mechanism. It's a process of elimination, so look into other aspects first and if no luck then it's something the dealer should look at.
You can start by eliminating things like spark plugs, throttle cable slack, any vacuum leaks and check to see that all connections (water, vacuum) to the throttle body are in place and secure.
The IAC mechanism is visible on the left side of the intake manifold. You'll see a series of hoses routed in a "U". Sometimes a faulty IAC valve/solenoid will make a ticking noise at that location.