Idling and stuff

[quadracer111]

Hello,
Looking for some input on an issue I am having with my 94 gtr.

Last summer my car idled fine, the occasional little miss every 30 or so seconds that is always found with aging coilpacks (from what I have seen/read).

Now at the beginning of this summer my car would idle high at 1100rpm no matter what. Then one day it now idles normally around 950rpm. However the whole car feels like it is rumbling a bit. It's not bad like it's missing a cylinder, but it is there, almost sounds like a mild cam.

Pictures of idle rpm, vacuum on stock gauge and an aftermarket gauge as well. I thought the vacuum looks a bit low. Airleak? I could swear my gauge used to read lower negative vacuum, near where the red line is on the a/m gauge.






Video here you can see my shift knob moving slightly, gives you an idea of what you can feel throughout the car. Also can hear exhaust.

http://s658.photobucket.com/user/quadracer111livecom/media/VID_20130703_154346_zps204cc296.mp4.html

[Skym]

Check for intake airleaks around MAF's to eliminate stuttering from MAF's getting 2x airsources instead of one.

Next would be intake gaskets (common failure on GTS, GTR engines causing missing). Wideband in exhaust would tell you if engine is running too lean.

The common miss at idle every so amount of seconds is caused by o2 sensor making ECU make engine go too lean (lean missfire), then rich and then lean again. ECU tune helps to fix this problem. Faulty o2 sensor can cause idle rpm to fluctuate slowly (lean = revs rise and rich = revs drop), as is very lazy. Unplugging o2 sensors should eliminate them as a cause, but if have a intake gasket airleak, weak fuel pump, leaking exhaust manifold gaskets or anything that makes engine run leaner, it's not a good idea to unplug o2 sensors.