This tool provides general guidance — not professional mechanical advice. Always have a qualified mechanic inspect your vehicle before making any repair decisions.
#1 Most Likely
Engine stalls at idle or in traffic
Typical Cost
$100 – $600
Idle air control valve replacement typically costs $120–$350 per industry repair data (2024). Throttle body cleaning may cost $80–$150. Mass airflow sensor replacement typically costs $263–$408. Urgency reflects worst-case cause (stall in traffic). Prices vary by vehicle make and region.
- Dirty or failed idle air control valve
- Dirty throttle body reducing idle air flow
- Vacuum leak causing lean idle condition
- Failing mass airflow sensor with incorrect readings
- Failing fuel pump with pressure drop at idle
An engine that unexpectedly stalls while idling or stopping in traffic may indicate a failing idle air control valve, a dirty throttle body, a vacuum leak, or a failing fuel system component. In the worst case, stalling in traffic or at an intersection creates an immediate safety hazard.
What a mechanic will check
A mechanic will likely clean or test the idle air control valve, inspect throttle body cleanliness, check for vacuum leaks, and scan for fault codes. Fuel pressure testing may be performed if fuel starvation is suspected.
What to say to your mechanic
“My engine stalls sometimes when I am stopped at a light or idling in traffic. Can you check my idle control system, throttle body, and look for vacuum leaks to tell me what may be causing it? I am concerned about it happening in traffic.”
Script based on industry repair procedures