Is my car done for? 2007 Lincoln MKZ

Hello! To preface I do not know much about cars, I really just want to know if these issues are fixable or if I should just look for a new car. I have a 2007 Lincoln MKZ and it has almost 145k miles. Yesterday evening as I was leaving my house, the check engine light was flashing (never done that before) and the car was super jerky when coming to idle and reversing. I also noticed the steering wheel was shaking while in drive. I used one of those code machines and the codes P0203 and P0303 came up. Earlier in the day and for the past couple of months I have had no issues with my car, the only issue I had was in the wintertime as I live in Michigan and that super cold front killed my battery. I did recently also get a back tire replaced, but I don’t feel like that should have any influence on what happened yesterday. Should I look for a new car? Thanks!