dashpot

New member here guys. Can anyone help me? My 2.2 l truck has an automatic trans. If I disconnect the vacuum line to the dashpot, it idles and runs ok. However , with the vacuum line connected, once I put the truck in gear it wants to surge and die repeatedly. ANY ideas why it runs better with the line disconnected ??? Thanks

Not sure but my guess would be a crossed line people throw em together all the time without lookin at a diagram.