Timing stayed true as it idled and started running bad. Awesome.
Checked the FPR and unplugged the vacuum line and capped the nipple on manifold and it idled perfect and not once stumbled. Took it for a short test drive and had hardly and take off power but ran fine, so I'm 95% sure I've found my issue. I've got a new one already so we will see what happens when I replace it.
Fuel pump has been replaced before I got the truck so I think that's good as well as the filter.
Let's hope this is it.

91 (Gen1) Monty, 3.0L V6, Auto 4 Door.
Disabled Driver.