With a smooth properly running motor you can drive for a long time with a broken/worn out motor mount and never know.


Here are my guesses,..

harmonic balancer
flywheel
clutch
pressure plate

Timing chain? Possibly jumped time?

Fuel injector came unplugged, defective or clogged? Possiby an entire bank came unplugged?
Spark plug wire disconnected, or plug fouled?
Vacuum lines?

Difficult to second guess,..

but any of the above can perform what your describing.

Start with the basics and what you can visually see first. If nothing found,.. open it up.

Worst case scenario you chucked a rod cap,.. not likely but possible.

Hurst