Yah also just check I know with the Rb25's they have problems sometimes when you start upping the boost through boost controllers without setting them up properly after on a dyno to check air/fuel ratios. Also if you have a Boost controller like a turbosmart T piece, just double check the conections. Also a leaking BOV can cause strange vac problems(mine did after leaking boost past the seal/oring) solved by puttong standard back on. Just little things. Is the charcol canister working correctly, mine was rooted inside causing vacume to bypass the manifold. Yah man just double check everything. Chris's car was also fixed by taking out a dodgy piggy back computer which was slapped in by the previous owner without getting it tuned after. Hope that helps.