Thanks fellas!!
I'm still not doing a good job describing it though..... let me try again (BTW this is my 3rd VQ40 powered vehicle also had 6 (if memory serves) VQ35 powered vehicles before this one..)
- Engine is smooth during normal and hard driving
- Transmission is smooth during normal and hard driving
- When stopped in P or N very smooth idle at a tad above 700 rpd (indicated). Always idles smooth in this condition which precludes Idle control valve in my mind and also precludes injectors). Just as smooth as my Xterra with 87k miles and recent throttle body clean/induction service...in other words as smooth as you will ever get a VQ40
- When stopped in D, foot on brake however
sometimes the revs go down to 500. The transmission seems to "catch" a bit... then and only then the idle turns very rough .. To me its feels as if the clutch is "catching" like when you are in a manual and partially release the clutch to ride it a bit on a hill start.... at the edge of "catching" it will push down the RPMs and the car will vibrate as it nears its stall point.
- I am now probably making it sound worse than it is but that is the best way I know to describe it.
. When I have time maybe I will check the plugs...
So much about this vehicle seems so well maintained and it pulls so hard and shifts so well..I would not be surprised to see them fresh but we will see