does the one coming from the plenum come around to the first t bit that gose to the back waste??
so if you are on boost and take you foot off the presser from the plenum pushes the waste gates open rite???
have u got spark?? and check if the fuel line is clean. all coils are on,
get your hands on a new batters or hook up a jump starer pack soo you no you got full power
but yeah it could be some thing simple but i dont know