a pooing issue

My cat is turning 6 months this week. For the past week he's been exhibiting very unusual behavior. Ever since I adopted him as a baby from the shelter he never had an issue with using his litterbox. As he grew larger, I bought him a bigger litterbox with a cover and flap-door. This past week he has peed and pooed on my roomate's bed. Me and her haven't been getting along this week, which may be a coincidence or not...so we decided its best if she kept her bedroom door closed. Still, for the past two days I have found poo in my bathtub, right in the center of the drain. I bought him a larger litterbox with a lid a month ago. I noticed that sometimes the flap door gets jammed and my cat would meow, probably in fear of being trapped. So I got rid of the flap door one day and he still used the tub. Now I got rid of the top cover in general, hoping this won't turn into a habit.

He hasn't been aggressive or destructive other than this...
I have him scheduled to get neutered in less than two weeks...Is his acting out hormonal?, or does he feel the animosity between me and my roomate? There hasn't been yelling in the appartment, so I don't know how he would know. What can I do to get him to stop this, or should I just wait until he gets fixed.

Thanks

Answer by Kate
I would say that this behavior could either be scent marking due to the fact that he not neutered yet, this is a common way to mark out territory especailly if they do feel some tension in the air. This may sto once he has been neutered. The other reason could just be that the litter tray makes him feel insecure and so does not feel comfortable using it. Making sure it is in a quiet spot not near his food is a good place to start. It could also be the type of litter you are using, he may just not like it. There are many on the market to try.
You may have to go back to litter box traing as described on my traing pages, where you isolate the cat with the litter tray for a few days to familerise them with the process of using the tray.
Good luck and best wishes

---