i had a small pin hole coolant leak in one of the hose that leads out the heater core. now having these problems. fixed the leak with a new hose. refilled coolant (was empty). im guessing all the coolant leaked out. still having problems. car starts at 3k rpm, wtf.... when it warms up it goes bewteen 2k-3k, back and forth like it is starving for air or fuel.... 100% sure that its not the throttle cable. changed spark plugs, wires, oil, oil filter. can't be the IAC valve, can it? i just hope its not an internal problem. but.. there was oil on the old spark plugs i took out. =/ i guess ill mess with the iacv tommorrow. any suggestions are welcome.

 

vacuum leak? im bored...

 

i had similar problem when my car is running start at 3k and warm up between 2k to 3k then driving around back normal idle between 800 to 1k but putting in neutral back to almost 3k, and im still tryin to figure it out....

my suggestion cleaned inside the iacv and let it dry for abt 30 min and see wht happen, its could be vacuum leak unless do the vacuum compression test if u got one

 

problem solved, it was the fast idle thermal valve. cleaned it now works fine. plastic piece was loose. =]