P1399 code what is the fix?

Question

pulled 4 codes at once. oem honda p0300, p0302, p0304, p1399

Answer 1

P0300 Random misfire

P0302 Misfire number 2 cylinder

P0304 Misfire number 4 cylinder

P1399 Random misfire

P1399 is misfire caused by EGR port being plugged,what happens when a partially plugged EGR passage , causes the EGR to open sooner and stay open longer creating misfire, You are going to have clean the EGR passage out or remove the intake manifold to get at it aggressively