Rough idle has me stumped

[Velislide]

Okay, I've been reading here since I got my WRX, about the rough idle issues. Cant seem to pinpoint whats wrong. Heres what my issue is like.

Starting, car starts right up and jumps to 2k rpms or whatever when starting, and when its settling back down sometimes it will just die, otherwise idle will drop extremely low to the point of it not registering on the tach, and then idle back up.

Sometimes coming to a stop, letting off the gas completely, will have the rpms drop to the point of it stalling, though rare. Car drives great and pulls hard. Isnt burning any oil, changed the oil not that long ago and it looked good. Its holding 14-15psi on the stock boost gauge.

So far, I've cleaned the IAC, changed out the plugs, cleaned all connections I can get to, cleaned the turbo inlet lines, vacume lines and T fittings, changed the air filter, cleaned the MAF, reset the ECU numerous times.

When hooked up to a code scanner, it said misfire on cylinders 1, 2, 3. Everything else checked out fine. At this point, could it be injectors? I dont have a ton of money, so taking it into a shop is pretty much out of the question. Car from what I can tell is stock, besides a catback exhaust that is way, way too loud.

Also I'm thinking intake gasket? Could that be something that would cause this, if it was leaking?

[Anub1s]

Well, usually that's indicative of an IACV problem (which you've addressed, though I really hope you replaced the gasket for it as you should have), or a vaccum/intake leak. I take it you've looked for cracks or breaks in the intake and charge piping, as well as the vaccuum lines?

Misfires can be another issue altogether, though. Have you performed compression and leak down tests yet?

[Velislide]

I havent performed any compression or leak down tests, I'll have to do some reading as I've never done those before on anything. My gasket was slightly expanded, so I popped it in the freezer for an hour and reinstalled, and checked after fully warmed the engine and drove around for awhile, no issues or leaks, though I will replace the gasket tomorrow if the dealer has some in stock, otherwise I will order one. My IAC was extremely gunked up, cleaned it down to the bare metal. I didnt take off the plastic end though, should that need to be taken off and inspected?

I looked at the intake as best as I could, maybe I will need to fully disassemble all the piping and inspect it?