I had the same problem at around 100,000 miles. Changed all 12 plugs and plug wires.
All ok since then.

I also had a stuck-closed EGR valve - and all THAT does is remove some of the throttle delay - so much so, that I put a switch on the console to disable the EGR when I want to get 'zippy'.

How many miles do you have on the car since you changed plugs and wires?
My other guess would be marginal fuel pressure - you could measure it, memory tells me that the manual specifies something like 55 pounds in the injector rail.