car is a 91 5.0. it was not idling at all so i replaced the ignition module. it idles and runs very well now... until about 3800 rpm. with and without load it falls flat on its face (sounds like a soft touch rev limiter almost) at between 3500 and 4000 rpm. since it happens without load as well as loaded i am assuming it is ignition related. i'm leaning toward a bad distributor. what do you guys think?