hi I have a bf xr6 turbo flashed custom tune sieman injector 2 half exhaust dual cat back typoon cold air intake boost is spiking from 15 to 11 psi thay told me maybe it is the cat converter. what do you think I dont wont change it for no reason I also get a bad smell after a few good hit please help by the way it was spiking before the injectors and the tune shop said I need bigger injector go them done same sh*t ?????????????????