Major Gen II issues

1. The guy with professional mechanic experience didn't know the Prius doesn't have a timing belt.
2. You should check/change your fuel injectors for the misfires. Has this motor ever ran low on oil or overheated?

 

how many miles on her, and have you kept up with maintenance?

 

timing chains have hydraulic tensioners, which can and do fail, teeth can jump
or a massive vacuum leak.....or sucked a bird into the intake system blocking airflow.....
road debris tear up some wires? ehhhhhh, more likely one of the first 2, but it's just so hard to troubleshoot from 500 miles away. Maybe not the TC issue, as I think the crank position is compared to the cam position and that should code out if the chain jumped or TC is really slack, but not sure.

multiple misfires
heat storage tank temp problems
heat storage tank valve position problems
idle air control system problems
evap system vent control problems/purge problems
catalytic converter efficiency

sure is a wide range of items.....if these are all new codes that came in at the same time, need to look for common thread.
if these are old and new mixed together, then some matter and some don't.

remember the basics....fuel, air and fire. and the right amount of each at the right time.

 

My car was running really rough, and down on power like you mention and throwing codes P0300, P0301, and P0302 (Random misfire, misfire cylinder 1 and 2). But would smooth out once it got up to a cruising speed. I did the spark plug change and replaced all coil packs with no change. Last night I took 15-20 minutes and changed out the cylinder 1 and 2 fuel injectors. Car now runs like a top! I don't know if this is your problem, but seeing the same misfire codes I was getting, you never know. When I have more time, I will replace the other 2 injectors which require removing more than just the airbox. The fuel injectors I bought were cheap ones on Amazon also.

dave