Wish I could help but I am new to the stang. I have a 97 GT Convertible Premium. Post more specs and check your suspension, steering, drive shaft, and wheel bearings first. I would try to isolate the shudder point, such as clutch area, and driving habits like slipping the clutch to get the revs up. By the way, my o2 sensor down stream are acting up too, but I know that I will have to tune it to get the check engine
codes out and improve engine performance. Whenever the light comes on I lose power, notable at the sound of the exhaust (flowmasters 40 series).
No pics posted yet, but will soon with self installed mods listed.