You're going to need to start narrowing it down. Just because you only notice it at hard throttle doesn't mean it's not there at idle. So I would suggest trying to figure out if it's a random misfire or if you're having an issue with a particular cylinder. Inspecting the plugs would probably confirm an issue with a particular cylinder. If it's random, then it will most likely be a little more work to figure out.
Try the easy tests first. You can do a quick test to see if you have spark to each plug. Just use a timing light. Clamp on to each plug wire and make sure it lights up. If one doesn't (or doesn't light up consistently) you may want to look at plug wires and distributor cap. If you have good spark to each plug, but one plug is "off" and doesn't seem to be firing, then inspect it and make sure it's not cracked.
A bad tps, dirty maf, wrong fuel pressure, wrong fuel mixture, bad injector, bad injector connection/wire, damaged plug wire, corroded or worn cap/rotor are some common things to test. If the ignition and fuel systems check out ok but you are having problems with one or two cylinders in particular, then start checking valvetrain. Rocker adjustment is a common problem. It's pretty easy to mess up the rocker adjustment process.
