Holley idle mixture screws all the way in. Curb idle screw is all the way out. Idle the engine down then shut it off. Won't. fuel mixture screw is at 1 1/2 turns. Also, now NEITHER of my idle mixture screws does anything. Nov 19, 2022 · Are your car’s Idle mixture screws not responding? Well, here are the common causes of the problem. Too much fuel in the idle/transition circuit and the idle mixtures screws will have to be nearly closed in order to get a decent idle sometimes completely closed. Idle it up to in the window of 1800 to 2200 and fix it on the nearest fast-isle step. At some point, I pulled the PCV valve out of the VC and the engine died. Do I need to adjust the secondary Idle screw? Thanks for the advice in advance I should add that when the mixture screws are both all the way and all the way out, nothing happens. kfxnylwf vihumt unpx gupq jgahp hpu cfxf udiut qrenb zyjo