when i start it up and drive it, it seems ok. When i get on it though it starts to miss. i have a new bosch fuel pump,new fuel filter, new fuel regulator, new spark plugs. i replaced one of the spark plug wires because it was burnt but it still misses. i am not running any smog or cat on the car. so it couldnt be a clogged cat. what else would it be? the fuel pressure gauge at idle pin doesnt stay still at all either. specs of engine in sig

 

Can you datalog it? Sounds like lack of fuel to me.

 

well i also have a fmu so it can control more fuel under boost but that is screwed all the way in and didnt help.