Code reads PO333 01/02, took it to Autozone, they said it was a Knock Sensor.

What is your question?

About a month ago, I traveled about 150 miles to visit my sister. My car stayed parked for a couple of days in about 30 degrees, and at one point, my lift gate would not open. Then, when I was getting ready to leave, my car did not start, and I needed a jump. I made it back home, and my car was fine, and the lift gate was also fine as well. Then 3 days ago, the Engine light and the traction light stayed on, not blinking but on, and my cruise light was blinking. When I opened the hood, I noticed that the Mass Air Flow Sensor was loose, so had it tightened. Could that be the issue, if so how do I clear the code? It seems fine, but am weary, if something is wrong.

What makes this problem better or worse?

Probably cold weather but not sure

How long has your 2012 Subaru Tribeca had this problem?

3 days