Trying to find out why my 2003 f350 keeps stalling when I hit the brakes I replaced high pressure pump low pressure pump but it still keeps stalling can some one help me please it has a 6liter in it

 

Does your truck have Hydroboost brakes or vacuum pump to provide brake assist ?

 

It's got hydro boost brakes

 

If applying the brakes brings up the problem, then we need to see what is affected involving engine function when power steering system which supplies power for Hydroboost brake system is activated.

The diagnostic path could start with looking under the dash to see if any wires are touching something when they should not when brakes are applied.
Simple, but necessary to make sure the simple things are checked first.
Since the power steering pump supplies the power for Hydroboost operation, it would be a good idea to thoroughly check that part of the system.

 

You need a good scan tool like FORSCan or FORScan Lite. Codes could help.

Also, I would be watching the high pressure oil number AND the IPR % Duty Cycle when driving. The HPOP isn't the only component in the HPO system that could contribute to such behavior.