Cold (Fast) Idle Rpm

1986 GMC Suburban C2500, 5.7 M, StandardSECTION Cold (Fast) Idle Rpm
NOTE: Procedures listed are for carbureted engines with adjustable fast idle.

Warm up vehicle. Remove and plug EGR and purge control vacuum lines. Place fast idle screw on highest step of fast idle cam. Start engine. On ECM controlled engines, wait until engine enters closed loop operation. Adjust fast idle screw to obtain fast idle RPM.

FAST IDLE RPM

Application Man. Trans. Auto. Trans.
4.3L Carb. 1800 (1) 1800
(1) Set Federal Low Altitude models at 2200 RPM.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.