2007 Pontiac Grand Prix 218,000 miles, automatic

Hi I’m trying to figure out how I can fix my car. I’ve been having trouble with it since the start of the month. First day of December it wouldn’t start and I changed the ignition coil module. Then I got it running and scanned it. It said I had a p0385 code for the crank position sensor and a p0300. I changed the crank sensor and seemingly the car was running better and the misfire was only in 2 remaining cylinders. So I was going to fix the misfire in the cylinders when suddenly my car started shutting down after starting leaving stuck in my garage till I figure something out. It won’t stay on for long enough for me to drive to a shop it seems should I put the old crankshaft sensor back in or could the problem be elsewhere? Thanks  for reading.