Yes the air filer and assembly is ok, the throttle body and top intake I removed a couple days ago and cleaned up by hand (the throttle body was really dirty on the back side, maybe because it has been running so rich on Limp Home Mode).
Thanks for the sudjestion, and yes I am fast running out of love for it.
Just wish I could park next to another LS400 and start swaping parts with known good units like ECU, MAP ect..
Don't give up. Have two or three days without touching it until you feel mentally stronger again. I am deadly serious - I have been there with other cars and many other malfunctioning things. (I could write a small book about my central heating woes.) Somebody will come up with the answer and since the engine itself is sound, it is likely something relatively simple. Have a rest. And when it is fixed, you will be DELIGHTED you stuck with it. I guarantee this.