By the past one month I am struggling to fix a random codes po 300 302 303 304 and 305. I have changed spark plugs,Plug wires, and coil Modula . fixed all vaccume lines . Still I have these error codes and the engine shuddering and shaking idle speed. Any one knows how to fix this problem? please help

might be due to one of sensors going bad or a problem in fuel system, although i would start with fuel, check your pump and filter