The original question seemed to be misfire at hard acceleration, maybe 3000rpm.
I am no mechanic, and defer to Russ and others, but I had the same problem for a couple of years. The car would hesitate and jerk a bit as I was accelerating, mostly in 5th gear. My remedy? I started changing out vacuum hoses, beginning from the carbon canister on the passenger side firewall, and worked my way to the driver side. Be very careful as you disconnect the hoses. Some of the parts are plastic, and I did break off the end of a solenoid (Russ got me another). I replaced about 5-6 hoses. The problem ended. I never knew which hose was causing the problem.