Rattle and Blinking MIL
This bulletin applies to 2013-2016 Honda Accord V6 vehicles. While driving under steady cruise between 30 mph and 65 mph, or during light acceleration, the engine may intermittently rattle or run rough, accompanied by a blinking MIL.
Since these driving conditions are likely to activate VCM operation, the probable reason for these symptoms is sticking VCM rocker arms. An engine rattling noise while going into VCM can be quite noticeable. What you’re hearing is the VCM rocker arm pin tapping against the other rocker arm as it tries to lock the two arms together going into valve pause.
The VCM rocker arm pin can also stick in its locked position, causing both rocker arms to stay connected. When this happens, the engine intermittently runs rough and the MIL blinks.
If the engine is shut off and then restarted when either of these symptoms happens, the rocker arms may un-stick, allowing normal operation with no misfire DTCs being set, which can make this problem tough to troubleshoot.
Be sure to check out the VCM (variable cylinder management) rocker arm test in the service manual. Replacing the affected rocker arm(s) usually fixes the problem.