Not sure how the misfire didn't just kinda scream at the problem. If the misfire and shaking is so bad, that should be looked into.
Check the plugs and wires. See how strong the spark is at the coils.
Possible that even the exhaust is completely clogged at the cat converter and not allowing it to rev. You can remove the upstream o2 sensor to give the exhaust another escape route, see if the car can rev higher or just loosen the downpipe at the rear manifold to allow the exhaust to escape before the cat converter, then see if it will rev higher.
