Engine Misfiring Damage

Hello, Compression test all six cylinders, log and compare the results. If you get good compression on all cylinders, you will want to look for vacuum leaks. If the engine turns out solid, no vacuum leaks, good compression, minimal pressure loss on leakdown test, and no engine noises, remove the camshaft position sensors from the front of the cylinder head (4). After removed, turn the engine by hand until you see a circle made of numbers through one of the crankshaft position sensor mounting location holes, and see if the same circle of numbers appears centered on the other cylinder head. If one cylinder head has the numbers centered in the hole, and the other is not, the balance shaft is the issue, and timing is way off. If that is good, you probably have an issue with the intake manifold where the control rods break. You can replace them cheaply, but you have to remove the intake manifold. Black smoke is from excessive fuel burning (running rich). Blue/gray smoke would be oil, but I doubt you lost three cylinders at once. TWC damage is a warning that the misfire will damage the catalytic converter if you drive it unrepaired.