Vacuum Manifold

[naval-avi8or]

Anyone know what the vacuum line that runs from the vacuum manifold block to the clean air tube (rubber tube from air filter box to the throttle body). I seem to have a slightly high idle until I disconnect and plug that vacuum line. With it plugged it will idle and return to idle normally if I have it connected it will idle high and over time slowly return to normal idle then if I rev the motor it will idle high again (1000-1500 rpm).

 

[SHOZ123]

There should be very little draw on that tube. It is used for the fuel emisson venting and power brake venting.

 

[naval-avi8or]

There should be very little draw on that tube. It is used for the fuel emisson venting and power brake venting.

That's gotta be my problem. Tried addapting my 94 manifold and it is supplying full vacuum to that line. The 97 manifpld must have some black magic internaly.


Thanks
Curtis

 

[SHOZ123]

Well if there was a malfunctioning canister purge valve or a bad firewall manifold module then there would be excessive draw. Try isloating the user side of that black box on the firewall.