84 s15 jimmy 4wd 2.8 2bbl...vacuum advance?

Does my truck have this. This is my first carbureted vehicle. I have been having vacuum issues. I replaced a vacuum line on the side of my distributor and drove it and the truck ran horribly. Took it off and it ran better. I have been having issues with lack of power when cold and hoped that fixing the vacuum leak would help. Any input would be great. Thank you.

If it runs real bad with vacuum line hooked up chances are you have a broken wire on you pickup coil inside the dist.
when the vacuum is applied the coil wires move and if a wire is bad it will lose contact.
You will have to remove the dist and take it apart to replace the pickup coil.
And always set base time with vacuum line unplugged.
MT