i have had this problem from day one with my turbo setup. If i build over two psi the a/f goes way lean, at around 4psiit falls on its face and starts to back fire.
at first i though it was the missing link so i took it off and blew in the bottom of it and was unable to blow trough it. I reistalled the map sensor with out the missing link and the performance is exactly the same.
i have double checked all of my items, i have a small boost leak at the BOV. The fmu is plumbed down stream of the stock FPR with the line to the tank coming out of the center fitting. I am at a complete loss and no one on another site was able to help me.
