90 stalling issue solved

[rufcar]

In the end my friend has a 91 and we swapped his parts to mine and vice versa. Nothing helped, then he remembered from his days in GM class about how gm could not solve the problem but came up with this adjustable vacuum valve inserted into the T fitting above the fuel pressure regulator. It no longer stalls. Though I can force a stall buy going say 50 and come to a fast stop to zero without downshifting. I can live with that. He didn't remember what the part was called or where to get one, but he had one.