Volvo: 1996 volvo 960 running rough, high octane fuel, 1996 volvo 960

Question
Hello,
Recently my 1996 Volvo 960 2.9liter fuel injected 6 cylinder, 125k miles is running rough. It starts fine, I can rev the engine in park, and she sounds strong through the entire range. When I get on the road, she bogs down bad. When I let off the gas, she slowly climbs. No step down power. I can put it in first gear and wind it out and it runs smooth. It is when I make sudden gas pedal moves it bogs, almost like a flooded carb. Transmission seems to shift fine.
Coil packs are new. Spark plugs are white in center and black around gasket area. The only vacuum leak was a brake booster that I replaced. Car was running the same before and after. I use top fuel and recently ran some injector cleaner through the tank to no avail.
I recently replaced radiator and the thermostat.
I was wondering if the engine temp fuel sensor (not the one hooked to the dash) might be bad. Only other idea I have is a clogged fuel line or knock sensor. I appreciate any help,
thanks, red  

Answer
It sounds like your car has asthma.  I would check the air intake and exhaust flow for clogs/obstructions.  I doubt it's a clogged fuel line, because you said it revs in park.  
High octane fuel is designed for cars with high compression.  Unless you've done some custom work, you're just wasting your money.
If this wasn't enough, feel free to ask again by 5pm(est) Thursday, that's when I return to my automotive class, and I'll have access to more information.