i have a fluctuating idle as well and i saw the other thread but i have some things different. mine will fluctuate from 1k to 1.9k rpm. im in chicago, its really cold and i start the car, and let it warm up for 10 mins every morning. as i was coming to my car, i hear the inconsistancy in the idle.

i got to the car, it drives just fine, but when i come to a stop, it fluctuates again. after it gets a little warm, it stops and will idle normally, any ideas?

d15 5speed in an eg8

 

hopefully i can get an answer soon as ill have time to work on it before dark. i read about the iacv. but can i remove it without coolant leaking? and is it on the bottom of the manifold?

 

do the usual.

get a can of carb cleaner
1. clean the intake manifold
2. throttlebody
3. check plugs - if fouled up, replace with NGK BKR6E-GP
4. Check iacv
5. check cap and rotor - clean contact points

 

good thing i made this thread. turns out my coolant was low. water pump is leaking and i didnt know. coolant got too low and caused the fluctuation. as it continued to leak, it just got worst. i ended up almost dry.

i put more coolant in, flucuation is gone. but waterpump still needs attention. i hate working on my car in the winter. getting it fixed tomorrow. driving to work with coolant in the car, lol

 

glad you got it pinpointed, if you can find a replacement brand like GMB - its a pretty good wp, been on my car for 4 years with no issues.

Tevs