e4od shudder in OD

With my 3.9 pushing my f150 and e4od transmission I am having problems on the highway. When running around 70 and going up a hill I will start to slow down and temps start to rise. No biggie, but when I push my foot on the accelerator the truck starts to shudder or buck if you will.

Running a quick 4 controller with the converter locking up around 50mph

thoughts or ideas?

Thanks