Painless, I'm a bit of an idiot, and pardon my ignorance, but on your truck, what is that resonator for that's attached to your throttle body??
I wonder if by the very nature of that dang thing if that's part of the cause of your lack of mileage improvement where you're piping that stuff in. (hope that makes sense)
I guess if i understood why dodge put that there, it might make more sense to me and my idea might seem dumb.. LOL.. seems as if the path of greatest suction (inside the resonator) is direct to the throttle body from the big gaping hole (plenum attach point) .. now common sense tells me that the whole resonator 'may' be under a bit of vacuum, and if you're pumping INTO this thing, the motor SHOULD get some of it, but still, i wonder if that, by it's nature and construction, is what you're fighting against... I mean, if you could get HHO into your motor and trip the CEL then you know you're doing something.....although you'd then have a different problem to contend with...
still... (sorry for thread jacking)... I wonder if you just got a cold air intake of some kind that eliminates that stinkin resonator, them plumbed in your HHO if you'd see some difference...
just thinking out loud.. you've got a GREAT setup... seems fishy that you're not seeing anything from all this...
oh well... hope i helped