My car stalls when I stop at red lights or come to a stop sign. It restarts fine but keeps happening.
A car that stalls at idle but runs fine at higher speeds has an idle air control problem. The engine needs a precise amount of air at idle to stay running. When that air supply is disrupted, the engine stalls. The most common causes are a dirty throttle body (carbon buildup restricts airflow), a failing idle air control valve (sticks open or closed), vacuum leaks (cracked hoses let extra air in), or a dirty mass airflow sensor. Start by cleaning the throttle body: remove the air intake hose, spray throttle body cleaner on the butterfly valve and bore, and wipe clean with a rag. This 10-minute fix with a 5 dollar can of cleaner resolves the problem about 30 percent of the time. Next, clean the mass airflow sensor with MAF sensor cleaner spray. If cleaning does not fix it, have a mechanic check for vacuum leaks using a smoke test. A failing idle air control valve costs 50 to 200 dollars to replace.
