Idle Problem????

[xXx_Si]

I have a 2000 Honda Civic Si wit a B20 vtec swap, B16 head, and when the car is idling, the rpm's will rise up a little then go back down, at a slow pace, and after a while, it will go back down to a 1000, and when i rev it a little it will start again. When it starts, its idling at 1500 when it does it, and i have actually seen it happen at a 1000 one time.
Now i have checked all hoses to the intake manifold and every thing is tightly put in, all sensors are plugged in, and the engine light is not on, so i have no idea what it is.
PLEASE i need some help!!!

[.:Stirfry:.]

take off the IAVC on your intake mani, and give that bit a good cleaning with some purple power, break cleaner, or any other degreaser..

[Black4DrEK]

spray throttle body clean all around... maybe you will find a VAC leak

[xXx_Si]

spray throttle body clean all around... maybe you will find a VAC leak

I have already done that.

[scttydb411]

i'm guessing it's not tuned. what ecu are you running since there isn't a stock b20vtec ecu.

[xXx_Si]

It is tuned by Mainstream Performance, i bought an aftermarket one.

[xXx_Si]

bump

[steedracer]

IAC valve

[scttydb411]

if it was tuned there then i tuned it.

how long ago was it that it was tuned? did anything (i mean anything) change since it was tuned?