IAC controls idle by bleeding air past the closed throttle plate. Carbon-coated pintle causes stalling at stops, hunting idle, and stall-on-cold-start.
The IAC is a stepper-motor valve mounted to the throttle body that meters air around the closed throttle plate to set idle speed. Carbon from PCV vapors coats the pintle and seat, causing the ECU to fully open the valve but still not get enough air to maintain idle - resulting in stalls at stops, hunting idle, and dies-on-decel. Two T-20 torx screws hold the IAC to the throttle body. Pull it out, soak the pintle in carb cleaner, gently wipe (do not bend or twist the pintle - it is delicate stepper-motor output), and reinstall with a new o-ring. Cleaning works about 50% of the time; the other half requires replacement (Mopar 53030840 or Standard AC4). After install, the ECU relearns idle over a few drive cycles. To force relearn: disconnect battery for 5 minutes, reconnect, start, let idle for 5 min with all accessories off, then go for a drive.
| Part | Vendor | Est. price |
|---|---|---|
| IAC Mopar | Mopar | ~$70 |
| IAC o-ring | RockAuto | ~$3 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.