Ran 2 cycle oil at 1/2 oz/gal with no problems. Upped the ratio to 1 oz/gal and the pressure gauge now shows a very slow 15 to 30 seconds rise to full pressure when starting. Once its up there it runs at normal pressure.
Normally the pressure rise is pretty much instantanous.
I have a new 7 micron filter.

 

So if you make a WOT throttle run and the pressure pulls down, does it come down to normal levels or lower? And how fast does it recover?

I'd almost think that you have a clogged screen that might be slowing flow causing the slow pressure rise, but I'd expect to see lower pressures and slower recovery when fuel demand is high.

 

Idle is 8lbs; wot pull down 6 or 7 lbs. This is "normal and usual" for my truck. What is unusual is the slow build up to 8lbs when I start up. Usually the pressure jumps to 7 or 8 lbs immediately. I'm thinking I'll run to town and get a 10 micron fuel filter and some fresh fuel - see if that helps.

 

That little of 2 stroke will not have an effect on the flow mixed with the fuel. Just a coincidence I think.

 

Changed back to the old fuel filter and the pressure now jumps up on startup the way it used to! The only thing I can think of - I usually grind a couple of gaps in the top radius of the filter to let fuel get to the top where the pressure sensor is located - didn't do that and the filter fits pretty tightly in the Geno's filter housing cap.
So your right - not the 2 cycle oil.