First, pull the codes and list them here. With them, we will be able to give you MUCH better information.
2nd, the most common vacuum leak for the Job 1 engine is the intake gasket, Job 2 would be the elbow as explained above.
The bottom pulley is bolted to the harmonic balancer. If the pulley itself is bent, simply replace it. The balancer may be failing as well. It is a 2-piece unit. There is basically rubber that may fail and let the balancer not run true.
I would remove the pulley, restart the engine and see if the balancer runs true, if so, then replace the pulley you removed. If not, either the crank is bent or the balancer is bad...