Poop in the potty already!!!

I am so tired of the rowdiness and then sudden silence when I know Travis is taking a break to soil his britches!!!  He has no problem peeing in the toilet, and for a few days no problem pooping in it either.  I think I must have scarred him when I fussed at him for immediately pulling his pants up without wiping.  Could that be the problem?  Or is he just stubborn?

Not sure but I know I'm tired of it!  I'm ready to resign to Pull-Ups.  But they cost a ton!!!  Worse than diapers!!!  Granted, we should only need 2 per day - one until he poops and then one until the next morning - so they should last much longer than diapers ever did. 

We've been reminding him that he can't go to preschool until he can take care of all of his bathroom needs without diapers or pull-ups.  He always says, "Yes!  I go to preschool!"  But it hasn't sunk in yet. 

Please, oh please let this summer be a turning point for potty time!!!