PEA doesn't completely burn during combustion that's the reason it's considered to be the king among gasoline detergents, Since high pressure direct injectors are exposed to the combustion process they are subject to build up just like anything else in the combustion chamber. Dual fuel injection is a great idea in theory but now you've got twice as many injectors, two different fuel delivery systems and even more crap clogging up the engine bay. I plan on using a can of CRC GDI Intake valve and Turbo cleaner before every oil change , If I had one of those fancy misters they use in the shops I could use any number of professional GDI valve cleaning products or more DIY products that are already approved for cleaning the intake via a vacuum line like Gumout Multi-sytem or Seafoam, etc or even use full strength techron, it's not how it's recommended to be used but I'm sure it'd do a good job cleaning deposits off the valves. I was thinking about using extra additives in the gasoline because even top tier gas like what they have at Chevron only has like 400ppm of PEA in it, I figured that adding some from a bottle would be a lot higher concentration, but I have no idea of the specific chemical properties of the polyetheramines used in any additives to do stoichiometric conversions all I know is that the PEA is about 30% by weight in Techron Concentrated but without knowing the exact polymer used I don't know the weight per mole to estimate the particle concentration of 4 oz of Techron diluted in ~18gal of fuel.