95 Mustang GT Problem

I have a 95 Mustang GT 5.0, When i go to take off sometimes it jerks, like it doesn't want to go, especially when i hit around 35-55 mph it does it then it'll stop at around 55 and won't do it 55 and up, i had a friend check out the transmission and told me that the transmission was good, and that it wasn't slipping, i had another friend of mine mention something about it could be a clogged cat, I'm running Dual exhaust 2 cats, 2 flow masters. If anyone has an Idea let me know, i hope it's not transmission problem and could be a easy fix.

Could be as little as cleaning your throttle body with throttle body cleaner. A dirty throttle body can simulate a slipping transmission and also causes high speed shut downs.
Franco