lossing freon

my 98 sunfire a/c wont stay charged i 've put freon in twice and i even tried to see if it was leaking by putting in freon w/die and couldnt find anything any one have any ideas?

You really don't have much of an option here. You said you couldn't find a leak using dye. Did you look at the evaporator core in the dash? It is possible for a leak to develop there. Your only option is to find the leak, repair it, flush the system, and recharge it. I personally don't have any faith in that A/C stop leak crap.:frown: