The change in shift points could be that you accidentally adjusted the bowden cable. I think your model has one. If so there is a linkage bracket on top of the valve cover that has a cable that goes down the the transmission. If so that's the bowden cable. You can turn the white adjusting nut to change the shift point. I can't remember which way will lower the shift points, but a search here will tell you.

I second, or third the vac line disconnected causing the shut off problem. Check all the lines in the engine bay. You may have damaged one of the ports on the main vac line or just simple knocked one of the lines off.

Welcome to the forum by the way!

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