i just drop in 1996 lt1 pontiac pacesetter longtube, cc306 cam, promagun com cam rocker arms cloyes timeing set. i have stock crank stock injector and stock intake manifold and also never change any my sensor and stock pcm. When i crank my engine for the first time it shut off when it idling but if i rev it more then 2000g it will stay on (everything is connect right ) wat do i do

 

Sounds like you didn't get the rubber elbow between the MAF sensor and the throttle body on tight, or its torn. Is the MAF sensor facing in the right direction? Is it clean and undamaged?

You are definitely going to need a tune for that cam.

What did you "drop" the engine into?