If the check engine light is flashing that is not good. Do not drive it. If check engine light is steady on you will be okay to drive it the couple miles home. Rough idle could be caused by a LOT of things. Without the code being read to narrow it down it would just be random guessing. The two things you mentioned will cause that as well as computer problems, clogged injectors, fuel regulator, fuel filter...........the list could go on. If you have a checkers or auto zone near you you could have someone pull you there and get the code read for free. Or for $10 more than what Chump Boys want to charge for a "diagnosis" you can buy your own code reader. They run from about $100-170.