Weird Timing issue on a 86 I6 300cui
so rebuilt my spare distributor for my truck, new pickup, rotor, cap and case and vacuum advance module and have the weirdest thing happening
we set the timing to 10 degrees BDTC (originally tried 14 but then we got this problem so went back to stock adjustments) and all is well, UNTIL we connect the vacuum advance, then the rpm's drop and it sputters and wants to die out and idles really low, its got fresh wires and fairly new plugs and runs fine right until you connect the vacuum line. we ruled out weird vacuum issues since if we disconnect the hose and actuate the advance on its own it does the same thing. the truck is a bit of a hack job from the previous owner but everything looks to be hooked the same as the parts truck that i took the rebuild dist from (couldn't test with the old dist because the advance on it was broken thus the need for the new unit)
anyone experience something like this before?