My r33 was detonating so i bought a new fuel pump, same problem so i retarded the timing untill it stopped and now the car is gutless as and its running 10 psi boost. only mods are bov and cat back exhaust. has anyone had the same problem. what can it be? on my boost gauge when i start it up the most it goes to is -11hg. i thought it should be like -30 or something. i have been having this problem for months