I have a 95 Disc 1. For sometime I have been experiencing a problem with cut-out fluctuation, which I have posted elsewhere, but as yet no resolution.
I have replaced the MAF unit, along with a new idle bypass valve and tubing. Also the plenum chamber has been recently re-seated and silicon sealed.
The current issue is with an adjustment up on the idle to say <800rpm. Using the RAV instructions, I have clamp-of the idle bypass hose and adjusted the idle hex screw (left to right), anticipating the rpm to increase. The result is nothing happens, the revs remain stable down at around 650rpm. I have since wound the adjustment up n down with no effect.
Could someone please advise on the mechanics of how the screw works in the plenum chamber. Does it inside the chamber work directly on lifting the throttle valve, or is there a possible blockage in an internal air vent.
Appreciated, many thanks. Regards Tony G. Christchurch, NZ

 

i think you should look for a blockage in the passageway under that screw,or possibly in the IACV port and no, it does not touch the throttle plate, the screw regulates air

 

Thanks Rod