HI, 1995 civic lx d15b7, 5 speed. 439k miles.
OK so it starts and runs, but the idle is getting wonky. It will go up to about 1000 and then drop down to below the first mark on the tach. If I give it gas, it clears up and runs fine till the next stop light.
NO vacuum leaks runs great when its not idling>
Any ideas where to start with this problem?
Thanks

 

Not sure but it might be time to clean the throttle body and iacv.

 

took the iac off and cleaned it, same with the throttle body.
MUCH BETTER. Idles strong and steady.
Thank you