Service Engine Soon Light

[Fumanchu2.7]

I'm told its a vacuum leak somewhere, but I tried the starter fluid test and could not get the engine to pick up revs no matter where I sprayed it. I'm thinking its a sensor, but have no idea which one. I also inspected the gas cap for cracks or anything, but no luck. The only thing i did notice about the gas cap is that there is no pressure or hissing behind it when I go to fill up the tank. As high pressure as the fuel pump is, id think there'd be a little pressure behind it? Any suggestions would be helpful, thanks.

 

[someotherguy]

From your older posts, always helps to give us year, engine, any other info - anyway 1996 with the 5.0

Need to know the specific code #'s and any symptoms you are experiencing.

Tank is vented through charcoal cannister and purge valve; you generally shouldn't notice hissing from pressure or vacuum when removing the cap.

Richard