Question

p1399 code misfire 2000 Honda accord cleaned egr also replaced plugs . what next ?

Answer 1

P1399 Random misfire

This is basically caused by EGR port getting clog and causing the EGR go out of range, for now there is no trouble shooing tree that Honda has, but you can isolate to see if the EGR is truly at fault, get a soda can (aluminum can) make a shim out of it you will block off the EGR, and test drive a EGR obviuosly will code up, EGR, but your are looking for a misfire , if the misfire is still there the EGR is not a fault and a valve adjustment will need to be performed.Just remeber to remove the EGR shim