As mentioned above, assuming you're actually using a timing light and have the SPOUT connector pulled out, your timing might also be off if your harmonic balancer is coming apart and has slipped. My turbo actually killed mine pretty rapidly -- if you still have the stock HB you might take a look at it and consider a replacement / upgrade. Lots of other possibilities, like excessively rich mixture which will only ignite with advanced timing. Do yourself a BIG favor and have someone professionally tune your car -- otherwise the turbo makes it a ticking time-bomb.