2013 Hyundai Elantra leaking oil badly. Check engine light flashing and car began to smoke badly. Can not maintain any kind of speed, shakes

What is your question?

Shifts poorly, I’ve had to add a quart of oil every 3 days. Check engine light just started flashing yesterday. It is not overheating

What makes this problem better or worse?

Anything and everything

How long has your 2013 Hyundai Elantra had this problem?

About 3 weeks, and check engine light just started flashing yesterday