when i start my car, it jumps to about 2k and slowly comes down to proper idle, sometimes it jumps to 2k then to 1500 and bounces back and fourth (1500, 2000, 1500, 2000 etc...)
it only does this when in park bot nuetral or and other gear (its automatic)...i was thinking possible idle air control or idle air bypass, what do you guys think, is there any way to check either? btw the timing is not off

 

This was at the top of the page you posted on. It is worth your time to read this.

https://www.homemadeturbo.com/forum/...threadid=12879

 

I fixed mine and some others with a piece of hose to make the inlet port smaller in the IACV. It basically makes the engine get less air so it idles lower when its cold.