Now with the "Easy" setting things start to change a bit (some manual smoothing before tuning makes the changes needed smaller).

Attached VE is after two sessions using easy 30/30.
Now the top rows start to look continuous at least. But what the fat spot at 1500rpm/90% is caused by I have no idea.

I also have developed a stumble when I don't ease the throttle in (i.e each shift etc). Is that down to poorly adjusted options (acc enrichments, overrun etc) or something in the AFR table (too lean to be able to take sudden throttle input)?
I would like to suspect extras since it seems to be easy to get stuck in settings (need to turn things on/off sometimes to get rid of them even though they are supposed to be off)

 

Think if one could read/listen to well funded advise from the brain trust...

I finally installed a proper dual ground wires from the common ground point to the LC1 heater and signal ground (I had one common wire from the same spot before). A salvaged power adapter cable made the installation reasonable nice (a dual cable is nicer than two loose ones).

The noise was reduced considerably (less then half now) and the difference could easily be seen by bridging the connection points I made.

Not having a background in signal electronics it's hard to believe that it should have that significant impact

On vacation now, but the confidence that I can Autotune a even better VE-table when doing my next sessions is growing every day

Getting a 12V adapter for the T400 and strapping it in for a track session would be a nice test (If I can make that work, the complete solution (including my ability) is pretty stable), with "update controller" turned off (and probably back to "normal" by then).

 

Sounds like a lean spot created by auto tuning with targets that are a bit lean. I'd not recommend anything leaner than 14.7 for the bottom few rows.