the federal reserve is set to ratchet up on wednesday its efforts to withdraw the unprecedented stimulus it showered on the us economy after the coronavirus pandemic upended global economies two years ago fed officials are poised to raise their benchmark rate by a half percentage point and approve plans to start shrinking their 9 trillion asset portfolio the moves are part of a doublebarreled effort to slow the economy and ease price pressures that are at a fourdecade high   the fed wants to raise rates quickly but may not know where to stop   the fed has never successfully fixed a problem like this   fed’s message on interestrate path destination will be scrutinized