#idle problems

Engine Stalls at Stop Signs, Causes and Fixes Originally published on Tow With The Flow: https://towwiththeflow.com/engine-stalls-at-stop-sign-causes/ Quick Answer: An engine that stalls at idle, stop signs, red lights, slow traffic, is usually suffering from a dirty throttle body, bad idle air control valve, failing mass airflow sensor, or a vacuum leak. It can also be a fuel delivery problem. This is annoying and can become dangerous in traffic. It needs to be diagnosed, but you can often still drive to a shop if it restarts quickly. What To Do 1. Note when it stalls. Only at a full stop? When you come off the throttle? In gear only? In park too? These details help narrow the cause dramatically. 2. Check if the check engine light is on. If it is, get the codes read before anything else. Most auto parts stores read codes for free. A code like P0505 (idle control system) or P0171 (lean condition) points directly at the problem. 3. Try cleaning the throttle body. This is the first DIY step for stalling at idle. A can of throttle body cleaner and 20 minutes can fix it if carbon buildup is the issue. 4. Check for vacuum leaks. With the engine running, listen for a hissing sound near the intake manifold, hoses, or brake booster. A vacuum leak leans out the idle mixture and causes stalling. 5. Check the fuel pressure if you suspect fuel delivery. Symptoms: stalls when warm, hard to restart when hot, rough idle before it stalls. 6. Drive it to a shop if it restarts reliably and the stall happens predictably. Tell them exactly when it stalls, this is the most useful information they'll get. Most Common Causes What It Might Cost Getting codes read first is free and can cut diagnosis time significantly. Stay Safe - An engine that stalls in an intersection is a serious hazard. If your car is stalling regularly at stops, avoid left turns across traffic and high-traffic intersections until it's fixed. - If the car stalls and won't restart and you're blocking traffic, put it in neutral and push it to the curb before calling for help. - Don't ignore an intermittent stall thinking it will go away. Intermittent problems almost always get worse before they disappear on their own, they won't disappear. - Automatic transmission vehicles should not be put in park on a busy road to restart. Put it in neutral, set the parking brake, restart, and then shift into drive when traffic is clear. Need more roadside help? Visit Tow With The Flow for complete guides on car breakdowns and towing.