What moral hazard problem results from action by the federal reserve?

The price and value of money will decrease, leading to inflation.
Large banks make risky decisions understanding the Fed will insulate them from bad choices. This is true due to how the banks take advantage of the power the government gives them. Since they are able to hold onto the consumer's money and savings, they end up taking risks to ensure they keep that power.
The Federal Reserve may not set the US budget in time. Feds are always keeping in min the overall government debt that we are in. If they are not able to come up with the amount of money by the deadline they set, they do not have enough for the military and other programs.
The President may not assign enough Governors to the Board, thus giving too much power to people the President previously appointed. With the government not splitting the power with checks and balances, then the other sections of government will have an overload amount of power. This will lead to them being able to create any bill and laws they want. 
Naked short-selling, which is where people short-sell options on securities without first safeguarding the security is obtainable. This is where people are able to cheat the system and short-sell other factors of the feds.