could be a bunch of things but best thing is to clean it, maybe your getting excessive blow-by and might be sludge on the IACV.

 

if you want to test you idle air control valve unbolt it you do not have to remove your coolant lines i know on my ls the black with yellow stripe is positive and orange in ground what you do is unbolt it and carefully you put the wires on the plug firs because they are small and you dont want the wires to touch when you have your wires secure have someone touch positive to battery and ground to car you will here a click from the iacv if you dont it is bad replace it

 

Jesus Christ use a period somewhere in there.

 

This isn't grammar school he doesn't have to.

 

Thank you Captain Obvious.

 

coolant disappears? better fix that first before dealing with anything else

 

Wow, this thread is almost as old as my membership.