After market pcv valves are pretty much useless. Right out of the box they leak, best option is go to Mitsubishi and get a oem replacement. Be sure to check for leaks around your throttle body, fuel injectors, all vacuum lines, blow of valve, and intercooler piping couplings. Another possible leak point is egr valve. Use the search tool to find info about deleting it or replacing it. Good luck and welcome to the world of dsm

OP;

I may suggest a couple pieces of advice to add to your blt:

• Complete this procedure on a warm engine. (operating temperature)
• Invest in a small pump that will let you regulate pressure. (A pancake compressor from Harbor Freight)
• With the the PCV, OE is better than most other replacement options, but can still leak. A Kynar check-valve can help along with the OE PCV.
• You can also complete a blt by bypassing the compressor housing (but before the inter-cooler) to rule out leakage from the seal.
• You will have some leakage into the valve cover due to slight overlap of valves and piston rings.

On an unrelated topic, but helpful for you, would be to try a compression and leak-down test to get an idea about the general health of your motor. More information can br found here:

http://www.dsmtuners.com/threads/compression-and-leak-down-testing.338152/

gbd1039 is right I second his opinion......

I'm in love with your stock clean ride....I cant stress enough that your very first mod should be a wide band.....PLEASE PLEASE PLEASE do yourself a favor and get that after all maintenance is done DO NOT make any mechanical changes to your vehicle before you get the wideband installed. Trust me you will thank me in the distant future when you're waste deep in mods on that bad boy. The wideband will show you what a healthy tune looks like which this is extremely important for when you start upgrading and looking to tune to get the best out of your upgrades. If I could rewind the hands of time this would be my first mod no question...I wish someone had stressed it to me when I was stock.

One more quick thing to look at is if your throttle plate is fully closed. Take off the intake hose and do a visual. Can also loosen up the stop nut on the throttle body to adjust.

There is no spot where all valves of all cylinders are closed. However there is a range where all intake valves are closed which I recommend you do the BLT at (suggest 30-40* BTDC).
http://www.dsmtuners.com/attachments/intake-exhaust-valve-timing-turbo-jpg.128779/
http://www.dsmtuners.com/threads/degrees-to-close-valves.444971/#post-153071377