P0300, but complicated?

Hello, this post is going to be a bit crazy..

But I was on my work commute last night and I got to a stop sign, then started driving again and my car started shaking and the engine light was flashing. Called OnStar and they said it's P0300, but obviously random misfire doesn't exactly pin anything down. It shakes a lot and seems to be sluggish power-wise. As of this morning the light is solid when parked, flashing when driving. I went from work to my sister's place so I could grab her car as I live out of town.

However, my question is if anyone knows if it could be related to any of this:

So I had code P0171, followed by code P0011, and the dealership insisted it was the accelerator pedal and changed it, then they decided it was the ECM and changed that. I had to get a new clutch and transmission (it sat in winter for a few months and mechanic thinks maybe ice build up caused issues, pin in clutch blew a hole through the bell housing within 5 minutes of driving after it sat). Anyway, issue with p0171 continued after new everything. Turns out they left stuff disconnected when they done my AC and coolant was flooding everywhere, causing a ton of damage to connectors. Then they used the wrong size to check and stretched out the pins for my wire harness. Anyway, after a lot of drama, the dealership put in a new wire harness for free. They replaced the solenoids as well because the p0171 code persisted.

Anyway, idk if this could be plugs/wires because idk why it wouldn't give a specific code vs random misfire. I'm wondering if it is likely it could be related to the other issues? Camshaft sensor?

I haven't called the dealership. My mechanic doesn't think it's safe to try to limp my car the 30 miles to his shop. I'm financially tapped after the clutch/transmission replacement and very, very tired of being without my car. As I don't really trust the dealership, I do not like to even contact them at this point without some knowledge of what it most likely is so any help is appreciated.

"P0300 The Emissions System is not performing as expected. An issue has been detected in the Exhaust Emissions System which monitors and controls exhaust gases released into the air from the engine. If the vehicle is continually driven with this light on, the emission controls might not work as well, the vehicle fuel economy might not be as good, the engine might not run as smoothly and could lead to future repairs."

Is specifically what OnStar emailed me.

It's a 2009 5 speed.