Low Vaccum under load. 400C.I.D in (1975 Ranchero)

Hi i am Phil, I got a issue with low vacuum pressure under load in my 1975 Ranchero 6.6L It has the 400 CID i posted here because Bronco's also have the 400 so yeah


Earlier i had a fall out issue with Safeway Gas, which "F* OVER MY FUEL SYSTEM!"

i put some techron in it to get the idle issue and the spuddering now it was fine then i woke up and started my truck up now it has had a low vaccum issue.... When switching it in to R, D, 2, and 1 It reads low very low compression My gauge sits right on the deadline between good/poor acceleration when under load. what can be the issue now?

I also have a neighbor who owns a chevrolet cavilier that was doing the butting and the spuddering thing too so i went out and brought him some techron. His issue Stopped and mine stopped too but i am still experience too low vacuum compression.

btw prior to the day before let's just say i was a bit angry and i put the pedal to the metal. I doubt it has anything to do with that though because i saw other people in my local area with the spuddering issue due to safeways watered down gas...


what do i do and what do i check first? I assume i have a leak of some sort.