Check your fuel pressure regulator. If you can suck gas through the vacuum hose, your FPR diaphram is toast, and you should replace it.

Also, check your O2 sensor. Before you spend $150 or more on that, try this. I had a similar problem with my 1991 940 Turbo, and my mechanic suggested I replace my fairly new Bosch Platinum plugs with the copper electrode Bosch Supers one heat range hotter than spec. He speculated that the Platinums are not hot enough, and that led to incomplete combustion under high throttle. Have not had the problem since.

Once you replace the O2 sensor, you might want to try disconnecting the negative battery terminal overnight to set the ECU values to default.