I'm thinking I would toss in a regular MP dist/ECU for a quick test to see if that makes it dissappear. Wouldn't be hard to do with some jumpers. I keep coming back to capping/plugging the vac can hose makes it much better. We've checked that the can/hose ain't leaking & we've added back in the timing the can was providing & we've corrected the rotor phaseing.
Well isn’t possible that a broken valve spring would work better with less timing?
Take away the 10-12 degrees fromvacuum advance and your making it easier on it,
Seems logical to me.
Idk though I’ll pull the valve cover tonight and have a look at it.
