idling issue???????help me out please

[speedjunkie]

ok the other day my car all of a sudden was idling at 1800 rpm.So i idled it around in 3rd. it droped down to 800.10 mins later back to about 17 1800 rpm. i shut it off for awile started it up and it was back to normal at about 7 or 800.the next day 1000 and has bin idling at 1000 ever since. does anybody no what the hell could be goin on here thanks alot.

[300zx_tt]

Is it properly being cooled? My idle was over 1,000 when i had cooling problems. I also seafoamed my car. It did make it smoother. Check your hoses. They tend to crack after 17 years.