this isn't a testimonial, there's an actual question at the bottom.
back story - my 1984 turbo wagon has been sitting for the last 5-ish years, in that time i've put maybe 500 miles on it. as it sat in my garage i've slowly done work to get it back on the road (brake job, fluid flush and change, fuel filter, plugs and wires, cap and rotor, new starter and battery, etc.), including sorting some electrical gremlins and ECM issues, tracking down vacuum leaks, the normal stuff. the tranny is dying but i'm running it into the ground to justify a 5 speed swap.
presently - i've been driving the car to/from the grocery store, home depot, etc. to blow through the gas in the tank that's at least a year old. on the way home from the store last week the car started running poorly - missing, putting along, no power. last night i went hunting for a vacuum leak with my propane torch and didn't find anything as i very recently replaced most of the vacuum hoses, intake hose, PVC valve, etc.
the car was having a hard time idling and had a noticeable miss across the power band so i figured i'd run some seafoam to see if it'd make a difference. i pulled one of the hoses from the evap canister (the one that has crazy vacuum), sucked about 4oz of seafoam and the car almost immediately began running/idling better.
i shut the car down and let it sit while i fixed dinner, came back out to go around the block a few times and the car is literally running like new. idling perfect, running perfect, power is restored, no miss or hiccups.
what could've happened in the engine that such a small amount of seafoam fixed? could it have been some sort of a blockage in the vacuum line that i ran the product through?