RPM Fluctuate.

[FastBack 240]

I searched and really couldnt find what i was looking for so heres the question. My car cold idles perfectly at 1000rpm's. After warm up is over the RPM's are supposed to drop normally to 700. After my car warms up the rpms consistantly fluctuate from 500-700. Does anyone know what could be causing this? Thanks

[Got Sileighty?]

i dont have an answer, but wow, my car is very different. cold start = 1400rpm. idle = 700-800. my car doesnt dip down to 500.

[FastBack 240]

yea i noticed right at start up that it does idle at 1400 and then drops after warm up to around 700 or 750 but yea after that most of the time the engine fluctuates at idle. Im thinking is something with the fuel but im not certain. Also when I turn the lights on or I open the door and the seat belt track moves the RPM's also drop a bit. Could this be from the alt? Any imput would be appreciated. Thanks.