dtc definitions not found! please refer to vehicle service manual!

Question

after I cleaned the spark plugs and clean the EGR valve this code came up (P1399) without engine light. the car give off a little vibration

Answer 1

P1399 Random misfire

Honda and Acura associates this code as random misfire from plugged EGR passage and valve clearance, If this was the EGR causing this code condition you would not  have a little vibration but a noticable misfire,if this was the valve needed adjustment you would code a misfire for that cylinder. This code condition has alot to do with the sparkplugs and possible from the ignition coil.clear the code test drive the vehicle to where the misfire occurs it should code up that particular cylinder.

Answer 2

P1399 HONDA Code - Random Cylinder Misfire Detected

Read more: https://www.autocodes.com/p1399_honda.html