Still no luck unfortunately. Looks almost like a mechanical/fuel delivery problem, but i'm positive that it was fine before removing cat's. Tried completely disabling and removing rear o2's (as much codewords etc. that i could find in s4wiki and elsewhere). Disconnecting the MAF does nothing. Almost thinking of trying to tune fueling maps, but I guess that wont work if fueling is in some other "state" than normal. And yes, I dont know what i'm talking about