Quadrajet Carb Problem
Short answer: High idle with the idle screw backed all the way out usually points to the secondaries not fully closing (commonly overlooked) or the throttle linkage/cable/bracket holding the throttle slightly open.
Things to check:
- Secondaries closed at idle; the set screw that adjusts the butterflies.
- Throttle cable orientation — with the linkage relaxed closed, the cable eye should reach the linkage without holding it open; reposition the bracket/cable if not.
- A bent accelerator pedal holding the throttle (rebend to spec).
- Choke fast-idle step binding (a shot of WD-40/Liquid Wrench frees it).
- Float needle not seating, an idle-stop solenoid stuck, ignition timing, and vacuum leaks.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
← Frequently Asked Questions
