1994 F-150, 138K mi, 4.9l I-6.
Recently was troubleshooting poor idling/poor MPG issues. Replaced the hose coming off of the twin throttles…only to find another issue.
The vacuum comes off of ports just downstream of the throttles. There’s a “y” fitting, connecting the two hoses into one, common hose. From there it goes to some sort of sensor located around the intake manifold; however, after that it’s plugged with a bolt.
Where is this supposed to go? Based on the location of the ports by the throttles, I suspect the EVAP system ought to be hooked into this, but that’s a WAG.
(Oh and I tried decyphering the under-hood diagram…too much “alphabet soup” for me!)