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So where does this vacuum hose go?

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!)

The emission sticker is what determines how the vacuum hoses are connected. If you can’t read “alphabet soup”, find someone who can.


If you can deciper enough of the vacuum diagram to figure out which hose you’re dealing with post the alphabet soup relevant to the hose here. We’ll be able to tell you what the abbreviation means…

Purge line for the charcoal canister? (see the 12th diagram)