Common question. Its the TPS sensor on your intake manifold. It is supposed to regulate the idle off the intake manifold but has gotten wore out or gone bad.
The tps sensor is a funny thing to mess with and is usually rivited in to the throttle body so its hard to replace unless you remove the whole throttle body and drill out the rivits and replace with screws.
Throttle positioning sensor is the full term on tps.
If you look it up on photos in google youll be able to see when it is.
My crx did it before I changed over to full fuel injection and bought a new intake manifold and all new sensors.
It wont hurt the car and I know its annoying seince it constantly will rise and fall. If turning your heat and headlights down changes it then you might be able to up your idle alittle to reduce the chance the tps thinks it needs to be ajusted.
The throttle cable can be tightend by the two bolts and you can raise the throttle some to the point where it wont idle up and down but you get a idle of around 1200 rpms. If that dosent bother you go that way, or you can possible adjust your distributor forward some to get it to idle a little higher also.
TPS cost aroung 40$ on ebay and is easy to change if your confortable removing your throttle body. If you remove it, go for replaceing its gaskets. 12mm bolts all the way around and there is one bolt hidden under the whole intake setup witch will take you some time to work it off with a small socket wrench set up.
email me if you need any pointers, I have a few photos and can take some to give you a idea of what im takling about.
Sunday, March 22nd, 2009 AT 7:07 PM