Ok so i bought a 91 civic for 300bucks lol i know it's stupid but it ran fine on my test run which was short and it also ran fine on my 40 mile drive home. Within a week it would run fine until i turn it off then go to start it and it would run super rough for a min until i got the rpm up then it would go away. Now as soon as it warms up it starts running super rough with or without throttle and will even die if let to idle or during shifting sometimes. It's blowing lots of white smokeduring this but i did put sea foam in it so that could be part of it. I'm totally lost.