what is ur vaccum at? a healthy/in time motor should be at -20psi. if u are 100% positive that u have no boost leaks and its not at -20, then ur timing is wrong. if u are positive ur timing chain and gears are spot on, then re install the cas. to be positive.... take the valvecover off to see the markings on the cas. i would also suspect coolant temp sensor. ive seen some weird shit happen with bad temp sensor. lmk