Yesterday I installed a Hondata intake manifold gasket and everything was working great last night and earlier today, but I drove to our local car meet tonight and when I got there I noticed the idle was bouncing up and down. I have the idle set to 900 and what it was doing was slowly going up to 1300 and then it would drop back down. It doesn't seem like a vacuum leak cause it doesn't go all crazy, it just creeps up to 1300 and drops back to 900. It will do it for a few minutes and then go away and act fine, but then it comes back a few minutes later. It also doesn't do it when I turn my a/c on for some reason. When the a/c is turned on it idles fine.
This is the driving i did today, I pushed the car pretty hard hitting my rev limit (8200rpm) a few times cause I was messin' around and after I did all that it was fine and acting normal. When I drove to the meet tonight I floored it in 5th and went about 110 (5500rpm) and after i did that is when it started acting weird. So I think a sensor might of come loose or maybe a loose connection. The car acts fine when i'm driving it and doesn't appear to have a vacuum leak.
Any ideas on what this issue could be? Thanks guys

 

Idle Air Control Valve?

 

Wouldn't that cause it to happen all the time? I checked it and the hoses are still attached and when i took the intake manifold off i cleaned the iacv too so it should be good

 

with the car running, just spray starter fluid around the areas you suspect. when you spray the spot that causes the idle to act erratic, you've found your leak
a likely cause is that one of the lines which was removed/moved when installing the intake gasket may now be leaking. a lot of times these old lines don't like to be disturbed