Hey everyone, just got my SCT Livewire tuner with five star tunes. Only have tried the 87 so far and truck seems a lot more responsive And can for sure feel the boost increase. I'm new to turbo charged engines and reading the guages. What is the stock PSI in the ecoboost? And With the 87 tune if I let off the gas.. Psi drops to -11.00 and is steady at -7. Is this normal to have Negative PSI?