Last weekend I had a sudden lack of engine performance too. When I would blip the gas on down shifts the engine would bog. It happened right after a fresh tank of Sunoco 93. I ran through that tank (one day of spirited driving)and got an new tank of gas from a different Sunoco and she purrs like a kitten again. The towel heads that took over the gas station (coincidence
I doubt it) where I got the bad gas may have swapped out for the 89 garbage or had water in the batch.
Do the cheap stuff first, its usually something stupid and simple.