Joined: Nov 2002
Location: Sandhills of NC
I would check the idle control system. Different manufacturers call them different things (as do shadetree mechanics). Idle load compensator, idle speed control, idle speed motor, idle stop solenoid, throttle kicker, etc. Basically, they all work the same. It's a small plunger that will extend and retract, against the throttle, to increase or decrease the throttle opening based on engine load. For example (on my '95), when the A/C cuts on, the idle control system will increase engine idle from about 700 to about 900, to keep the engine idle smooth. When the A/C cuts back off, the idle drops back to around 650-700. This can be controlled by electronic means (signals from the computer), by manifold vacuum, or by both. If your truck won't idle, and you've discounted other tune-up items first (like plugs, wires, rotor, cap, spark timing), check the idle control system to see if it's working properly.