hi i had a look at my vacuum advance and there was no vacuum line going to it. so i connected one to it and to a t piece going to the tb and now there is a pretty bad missfire at idle. also now when i drive the car goes good boosts hard for about 10 mins and then i cant put my foot down at all or it shudders like im turning the key off. i have to feather it home with more than 10 hg vac. has anyone ever had this problem i did a search before i wrote this. any help would be appreciated.
Glen

could it be once it warms up?

nah i warm it up first but i just disconnected it again and it doesnt do it anymore. oh well i dont need the vacuum advance connected.

so it was running right before you connected it?

your vacuum advance diaphragm is blown. Replace the vac advance.