I was just reading your message, & just wanted to ask you if you leave the oven door shut the whole time the cake layers are baking??
bake the cake layers for the time it calls for in the recipe, & make sure that a toothpick inserted in the center of the cake layers comes out clean.
Do you let all of the chilled ingredients come to room temperature first, before adding them to mix up the cake batter? & if mixing the batter from scratch, are the ingredients fresh? & make sure you use Large Eggs, unless other-wise specified.
After the cake is baked, only cool in the pans for about 15 minutes, then carefully take them out & place on racks to cool completely.
One other thing, if you can buy an oven temperature gauge in the grocery store, they help very much, our ovens most of the time are not right on, our oven is 6 degrees off, so a gauge has helped in baking bread & cakes.
Have A Sweet Day!!
Carol