Good morning all i have a 2000 honda accord f23a4 5 speed that was throwing a 1166 and 1167 as well as 302,301,300,303,304 and 1399pd. i have changed the plugs cap rotor wires and plugs. i just replaced the upstream o2 sensor and have similar running issues. I removved batt cable and only codes 301,302,300 and 1399pd i have been running fuel treatment thru the tank every other fill up. It sounds like the unit has a miss. I did pull the plug wires and found that cyl 2 has spark but doesnt change the sound or performance of the engine. I am getting ready to check compression but it leads me to believe the injector is an issue but looking to find some ideas of what may be a common issue on these. it seems to look like plugs may be showing a lil lean. Love my new lil daily driver but not a fan of these ULEV

 

When was the last time the valves adjustment was checked or done? They should be checked every 30Kmiles.
Exhaust side is usually tight, this will cause a lean misfire from the valves hanging open.

 

I HAVENT DONE THAT YET GOOD SUGGESTION THANK YOU DIDNT THINK OF THEM CLOSING UP GETTING TIGHT ILL CHECK THAT OUT