I am also experiencing the exact same symtoms on my DI, im a mechanic and im stumped on this one. Ive checked the actuator it operates as expected. Ive cleaned MAF, sensor bypassed the solenoid, ive got a boost controller and wound that all the way up it can achieve and hold 25 PSI so I thought its more likely to be fuel related. Swapped the fuel filter and still nothing. It even has a new (second hand) fuel pump on it that installed a couple months back. No codes nothing. Somwbody who knows these engines better than me please help!!