Okay, please help me

[skaboomizzy]

I rarely play multis. But when I do this seems to be the pattern...

I play very tight, usually winning a few large pots when people call me down when I'm holding the nuts or close to it. This works fine in the early stages.

In the mid-stages (1h 30 min to about 3h) of online tournaments, I tend to play a bit too weak-tight and see my large stack whittled away via blinds and my open-raises re-raised. This usually ends up with me making the top 20-25% of a tournament but missing the money.

Can anyone give me some advice on how to play the 2nd and 3rd hour of a typical online multi? I'm usually afraid of re-raising into someone's pocket As or Ks, or some such. Also, my tight image if the table has been static reduces my action when I do raise pre-flop or on the flop.