i have two civic ex model cars and both of them have the same issue. the plastic piece that pushes the lock hook out on the trunk lock gets chipped away and then stops locking. Pain the the arse!!!! the only thing besides replacing it was just putting a bunch of tape on the striker to build it up and when you close it it help push it close. but it's definitely annoying! why didn't they make it out of metal or something??

What The HeLL - THIS IS so annoying the latch closes sometimes and not others

My trunk lid on my car won't stay closed. I have had a new latch put on (2007) and it started doing the same thing again in 2008. It is annoying to drive around, hit a slight bump in the road and the trunk opens. Sometimes if I hit another bump, it closes itself again. This was a definite pain while on vacation with all our stuff in the trunk. I saw another Civic yesterday with the trunk bungy strapped closed so I figure this is not an isolated incident.