2002 Ram 2500 loss of power hesitates and stalls give it gas it won't go over 30

Sounds to me like an air intake restriction or an exhaust restriction. Best as I can tell anything over the internet. Hands on inspection will be required, could be a quite a few things that cause this problem. The good news is that it seems to be consistent enough that a good technician with test equipment and knowledge should easily be able to get to the bottom of the issue.