My 04 WRX is only a few months old and Ive had this problem ever since week one. The problem is that the trunk doesnt always unlock when the unlock buttom remote is pressed. This is how it goes to open the trunk:

1: Press unlock on remote
2: Place key in trunk keyhole and proceed to turn it
3: The key won't turn, seems like its jammed
4: Give up and open the trunk from the trunk release latch from driver's seat

This is wierd because even when a subaru is locked you are still able to unlock the trunk with the key and set off the alarm. But my problem is that sometimes the keyhole is jammed and wont budge.

I am going to address this issue on my next oil change, but it only happens about 1 out of every 10 times. Anyone else get this problem? Any help would be appreciated.

This has nothing to do with your remote or the keyless entry. Since the trunk lock is strictly manually operated by either the key in the lock or the cable release, the alarm/keyless status has no effect on it. Your problem is a misadjusted trunk lock.

Yea i knew it was a mechanical thing. Just wondering if anyone else around has experience with this prob.

I had a similar problem when I installed my trunk light. (Yes, '99 Imprezas had no trunk light. I don't know if more recent models do, but I had problems about not having a trunk light.)

Anyway, my problem was I had to replace the trunk latch to get a light in there. If it was aligned improperly, the trunk was too tightly closed for the key to work. I had to find the sweet spot between too tight and too loose.

You can probably just take a wrench to the catch for the latch (on the car body, not the trunk lid) and adjust it up a little bit. If that doesn't work, it's probably something inside the lock. Sounds like a warranty item to me anyway.

I have the same problem with my 04. It doesn't happen all of the time, but sometimes it seems like I will break my key off in it. All I can do is go inside the cab and use the trunk release, and sometimes it seems like the plastic handle will break. I did see a post on here where someone lengthened a spring on the latch to fix the cab trunk release. Don't know if it will fix the key problem or not.

yea skyhawk exact same prob... sometimes it feels like it'll snap the key and the plastic trunk release. Just hope dealer knows how to fix it

I've had the same problem on a new 04 WRX, but it was even worse. I'd pull the trunk release handle next to the driver's seat, and the trunk wouldn't open (handle pulled all the way). Then I'd use my key to open the trunk and it'd be jammed for a few seconds until I jiggle the key in the lock a few times. This happened once every 10-15 times I used the trunk. I also noticed that the trunk needed a lot of force to close into the latch, otherwise it'd just bounce against the latch as if something was in the way.

A service manager first saw that there was no lubricant on the latch. Then we reproduced the non-opening situation after opening and closing the trunk about 10 times. After working on the car, he said they adjusted the latch. Now the trunk opens much easier with a pull of the release handle, and it closes with less force. I haven't had it jam up on me yet - 2.5 months and counting.

You can readjust the latch so the lid isn't pulled down so tight when latched (two hex nuts on latch) or push down on the center of the trunk lid when you use the key. Don't loosen it enough so thatg you get leaks.