Tenor, There are several possibilities, but it would appear that the root cause of your issue is VAC. improper vac to the shut-off valve will cause a your delay and improper shifting. Some of the possibilities include, the check valve (black and white plastic piece located on the drivers side near the fire-wall) or the connecting vac lines. or even the shut off valve itself. unfortunately the engine vac system is all tied together, so in reality the leak could be elsewhere.

Do you own a mighty vac tool?

This could help you track down any leaks

__________________
Dean