I am hoping someone can help me with my current issue as I have tried everything I can think of and am at my wits end with this car. It is a 2007 Aveo with right at 70,000 miles. A couple weeks ago it started missing randomly and then two days ago lost all power over about a 3 minute window and died on the interstate. I had it towed home where I ran codes and got P0300-multi misfire as well as every individual cylinder misfire code. I have replaced camshaft position sensor, plugs (copper core), wires, and intake boot (found large crack). It is still running absolutely terribly and occasionally dies trying to idle. I have checked fuel pressure (on, running, leak down) and all are in good range. I have verified no other vacuum leaks exist by using carb cleaner throughout. I can't think of what else it could be that's not throwing a code. I even removed the pre-cat O2 sensor thinking maybe cat was clogged and that would open it up enough to make a difference. That also had no effect. PLEASE HELP. Car is idling all over the place, won't pickup speed, and live code reader is saying that spark advance is going from -5 BTDC to +22. Gas pedal does essentially nothing unless you feather it very very slowly.