Start by cooking your rotini according to the package directions. Drain and set aside.
In that same pot that is now empty add in 1 tablespoon of olive oil. Cook sausage on each side until brown. Remove and cut into bite size pieces. Set aside.
In the same pot add your remaining 1 tablespoon of olive oil and then your peppers and onions. Allow to cook for 2-3 minutes until tender. Place sausage pieces into the pan and cook until all pieces are cooked throughout.
Add in pasta and marinara sauce to the pot. Allow to cook for 4-5 minutes until warm through out.