blinking check engine light means that the cat cannot filter the exhaust running through the exhaust,usually caused by a high amount of raw, unburned or unignited fuel usually pointing to a misfire
you might not be running on all 4 cylinders.
when was your last tune-up?
how do you know your engine needs a rebuild?
i've seen someone drive on 2 cylinders for almost 3 months only to find out he just needed 2 spark plugs but he was just too scared to have it checked out......