2001 honda crv 2.0 dohc -codes are in below for more info.to question

Question

i have a few codes reading 3months after repaired at honda codes are ..po300-po301-po303-453-po730-po450-p1399.this happen over a few months i thought it was a cracked valve on cyl1 & 3, then random miss fire came up,lost lots of power then the trans went from drive to low as i was driving it i manualy shifted from low to 2cnd to drive and seemed fine enter code herepo300enter code herepo301enter code herepo303enter code here po453enter code herepo730 enter code herepo450 enter code here`and this code has been on for yearsp1399 over the summer i replaced the -ecm-,coil-cap rotor -plugs -wires.-fuel pump.; only lasted a few months then would'nt start. so i towed it to honda and I was told plugs wires, cap ,rotor, was all that was wrong with it. so while they had it i had a new timming belt,new seals crank and cams as well as new tensioners on timming belt, a water pump, new belts and tensioners as well and complete ac compesser lines ect,,dryer condenser, radiator. and hoses ; it ran great after all that even took it across country twice in three months,,,,,, then this happen,,,, could the e.c.m I put in (after market)have gone bad again? or should i be looking else where for this problem help i;m out of answers.

Answer 1

P1399 Random misfire

P1399 is related to random mifire due to a pluged EGR port, what happens is you have 4 cylinder and a EGR system that is meter for 4 cylinders, if one or two of the EGR port is plugged, the extra EGR gas enter open EGR port that are open, What the EGR gas is is recirculated exhaust gas, Recirculated exhaust gas are inert which does not support combustion.. Because there is a misfire which result in incomplete combustion these gases get mixed with inert gas, which now support cumbustion and enter open EGR ports and upsetting  the fuel mixure which cause the misfire. The EGR port would need to be open and cleared.