I had the idle air bypass vavle go bad in my TB (the water controlled one , not the the electric ICS).
Ran me ragged cause I didn't know about they part and it's not in the FSM. Folks here on The WIRE set me straight.
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I looked into Mass Air as that seemed to be the problem with my unsolvable fast idle.
2 test on mass air (other than cracked wires at the terminal)
The little resister looking thing(visable) can do a ohm test.
The rest of the gizmo is the honeycomb air vortex control(it can get bent or gunked which make air swerl wrong. Air flow /dencity is measure with sound ways in the properly flowing air.
This part according to AllDataPro can be tested with an ocilloscope.
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((On my TB I ended up cutting gasket material to block 1 of 2 air ports thru the bottom of the TB and did away with water hoses.))

Last edited by KrzyDav; 08/09/14 12:06 AM.
dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.