Tom M'Guinn

In that case #1 is probably not part of the routing I drew above. My guess is it is either a hose someone added to drive an aftermarket boost gauge (do you happen to have one in the car that isn't working?) or it may be one of the HVAC lines that plug into the firewall (do you see ports disconnected on the firewall?).

You say #3 goes to a tee that goes to the AFR, but assume you mean fuel pressure regulator (FPR)? If so, where does the third leg of that tee go? And where do the other two ports from the #2 tee go? My guess -- just a guess -- is that the tee on #3 is the black tee in my drawing, and the #2 tee is the blue one in my drawing. If so, 2 goes to 3, and you just need to make sure the other ends of those tees are connected per my drawing, and then figure out what #1 is.

Does #1 have vacuum on it when the motor is idling? You can feel it with your finger if so -- no tools needed.

911lnv87

Thanks Tom, for all your advise, I ended up by connecting 2 to 3 and I have a feeling the car is smoother.

As per 1 it is a mistery ...