I have a 1995 F350 with a surging problem when I'm not towing I can feel a little bit of tugging but when I am towing (15,000 lbs) I get a stronger tugging forward and aft I have also noticed when shifting in 3rd and overdrive I will get a type of predominate tugging reaction some say it's my injectors some say my torchconvertor. But worse in a load.
Any help would be appreciated

It could easily be the transmission. When was the last time that you completely changed the transmission fluid and filter and serviced the complete drivetrain? In the 7.3 PSDs I've worked on, using Amsoil or Mobil 1 full-synthetic ATF (17.7 qts) has tremendously improved transmission towing performance, even in 100 degree+ weather. Be sure to also change the differential gear oil every 100,000 miles. Add 8 oz. of Friction Modifier (XL-3, Blue) first. Then, add 7.5 pts. Of 75W-140 GL-5 Synthetic.

If you still think it's your injectors, this link will tell you how to easily test and replace injectors:

https://www.askmehelpdesk.com/cars-t...ml#post1415281

Certainly would agree with a transmission problem. As well as servicing the transmission. More specifically there could be a problem with the clutch packs slipping in one or more of the gears selected. Best of luck.