why did my car lose the power to go?

What is your question?

it started with a slight miss or rough running and then the service engine soon light started to continually flash. then it just lost all power. it will start and idle but has no power. what could it be wrong and is it an expensive fix?

What makes this problem better or worse?

it prety much stayed the same whether it was cold or warmed up

How long has your 2005 Nissan Xterra had this problem?

a few days, maybe a week