car has trouble starting, what could it be? Options

[6strngs]

yeah, I've pretty much noticed this since a little before I got the car, but when I go to start it up after it's been sitting a few hours, it'll start, and the RPMs will shoot up to where they are supposed to, but when they come back down, they don't stop at 750 or whatever idle is and keep dropping until they reach zero and the car dies... so I'll start it back up, and in order to keep the RPMs up, I'll rev the engine. but as soon as I let go of the gas they drop real low again, so I rev again. usually, once I rev it to ~6000 and let it come back down it'll idle fine and then run fine for the rest of my trip, and if I shut it off for a while and come back, it'll be fine. but if it sits for 6 hours-ish or more before I start it up again it'll do it again...

what could be causing this?

[Negative]

The thing you think is your PCV is the spot where you had a tube running to the original stock intake? Look on my profile you will see a red tubing line running almost straight from my intake to the top of my valve cover. You mean this< If so that is just a vent to the valve cover. That's all. It does need to be vented however there is supposed to be a baffle plate that keeps the oil splashed by the cams from running into that line. You would need to pull the valve cover to inspect it but I can't think of a single reason why there would be anything wrong with it. If you pull that tube you should hear a loud almost metal cricket chirping noise. That would be the normal sound of the valves that is otherwise inaudible because of the tube that runs it to the intake. I know cause when I first hooked up an intake to my car I did not run that tube I just put a k&n breather on there. As soon as I ran the line back to the intake it shut up. Kind of like when you put your finger over the nipple.