Did the dealership drive it
Did the dealership drive it on a completely discharged battery? In order to get 34 MPG, one has to drive it like the EPA tests it. That means you can’t drive it at a steady 70 MPH (or greater) for long distances and expect to get 34 MPG, especially if you don’t have a full battery charge that you are using throughout that long drive. I am not saying something isn’t wrong with your Sorento PHEV - I have no idea of course - but if you ARE driving it like the EPA tests it, and doing at least 40-50% of your miles below freeway speeds and then accelerating gently, etc. throughout you should be able to get that MPG (unless something is wrong). The EPA tests are still not particularly realistic compared to the way many people drive, especially in states (like Texas) where speed limits are higher. Personally I think it would make sense if the EPA test were based on more aggressive, higher steady state speeds, not because that’s how I think people should drive, but because that’s how so many people do drive and if the tests benchmarked a worse MPG, people who drive slower or at a more relaxed pace would be pleasantly surprise at how much better their fuel efficiency was. Bottom line, no matter what kind of vehicle you drive, if you want to get better mileage you must slow down and drive more smoothly. I think that is what the EPA is (quite passively) trying to encourage with their current testing model.