idles smooth,but will not take any kind of throttle without running rough on 1995 Nissan 200SX

does not throw any codes, just started getting worse and worse.

Asked by for the 1995 Nissan 200SX
Start by having qualified shop inspect fuel pressure and volume and inspect condition of ignition related components. Please do not start throwing parts at it as you try to guess at it. A qualified diag is going to be cheaper in the long run unless you are a good guesser.