Need Help With Off-Idle Surge

It is coming in too soon. If you insert the mity-vac or vacuum gauge with T- inline, you can see what is happening to the ported vacuum. There is a release trigger on a mity-vac that will bleed the vacuum for testing. Tekslk, has a good idea, but the mity-vac will give you the numbers you need to tune. His test is great to first identify the problem.

I may me wrong on the ability to ability to adjust, I tune electronically with 3D RPM/MAP so I have complete flexibility.

Too much accelerator pump fuel, or a spill over could also result in surge.