I found leakage & clogs in my system which would attribute to the crappy mileage.

I used my eudiometer to check my production at the intake. For some reason it was .25 LPM.
Digging I found several issues. First my lovely reservoir leaked gas from the cap. I suspected in as much as that was the only part that was not in my bench setup. I swapped it out for the other one for now.

I also disconnected the circulating pump since my cell is relatively cool. Ok so then I blew air into the line from the reservoir to the bubbler, nothing. Can't blow the air into it. Why? The stone is clogged beyond use. I replaced it and ran the truck.

I see real good gas production at the reservoir. I test it at the intake... 2 LPM.
The scangauge is reading better mileage but still not as good as without HHO.
Filled up my mileage went from 15.5 MPG to 12.4 MPG.

I also threw an 1151 & a 1131 code (lean condition) My EFIE was set to 338MV I suppose this is due to the fact that not much HHO was getting into the intake.

I have to play with the EFIE now, maybe set it to around 355mv.