So my stock gsr turbo blew up on me after about a year and decided to put in a built LS VTEC motor with low compression pistons, and head semi built with dual spring and retainers. I used the same 1000 cc injectors, 3 bar map sensor, and s300 from the previous gsr turbo. The problem i am having is the car doesnt stay idle. When i first crank it, it turns on for a second and then turns off. After that i have to give gas for it to idle. It also sounds something is knocking in the head. I checked the timing belt, and the tps and map sensors are connected correctly. what else could be the problem? its my first time dealing with a brand new motor. FYI, the head is freshly rebuilt and so is the block.

 

with the built motor you put in did you get it tuned?